Sandra Rebelo

Purpose Cat-scratch disease (CSD), primarily caused by Bartonella henselae, is a well-recognized zoonosis with a broad clinical spectrum, in which atypical manifestations may delay diagnosis. This study aimed to characterize the clinical and epidemiological profile of CSD at a Portuguese tertiary care centre and to evaluate the role of molecular and serological methods as complementary tools. Methods We conducted a retrospective cohort study including all patients with laboratory-confirmed CSD diagnosed at Unidade Local de Saúde de São João, Porto, between 2010 and 2025. PCR-positive specimens were further characterized by sequencing for Bartonella species identification. Comparative analyses were performed according to clinical presentation (typical versus systemic disease). Results Thirty-nine patients were included (median age 15 years), of whom 53.8% were paediatric. Cat exposure was reported in 94.9% of cases. Information regarding flea infestation and preventive measures in companion animals was unavailable. Systemic presentations occurred in 43.6% (17/39) of patients, most of whom (94.1%, 16/17) were immunocompetent. Among PCR-positive specimens successfully characterized by sequencing, all were identified as B. henselae. PCR positivity was higher in lymph node tissue than in blood specimens (79.2% vs. 15.8%). The median time from symptom onset to diagnosis was 52.5 days. At the time of diagnosis, serology was positive for IgG antibodies in 76.0% and IgM in 28.0% of CSD patients. Azithromycin monotherapy was most frequently used for typical disease (81.8%), whereas combination therapy was more commonly used in systemic cases (76.5%). Clinical resolution after a single treatment course was achieved in 74.4% of patients. Conclusion CSD frequently presented with systemic involvement, including in immunocompetent patients. The prolonged delay between symptom onset and diagnosis highlights the need for increased clinical awareness, and improved access to serological and molecular diagnostics. Given the high frequency of cat exposure among affected patients, One Health strategies focused on responsible pet ownership, regular flea control and veterinary follow-up, may contribute to reducing Bartonella transmission and the burden of CSD.

Aim: We evaluated the diagnostic accuracy of ultrasound, postmortem and genetic studies in classifying skeletal dysplasias in the first vs second trimester of pregnancy. Methods: We retrospectively gathered data from a 15 year period of all the prenatal ultrasounds, autopsies, and available genetic studies on fetuses with skeletal dysplasias from our institution. Results: Five (23%) and 17 (77%) fetuses were diagnosed during the first and second trimester of pregnancy respectively. Only partial characterization was possible with ultrasound in the first trimester. Complete characterization was established in five cases (30%) in the second trimester with ultrasound alone. Pathology provided an additional diagnostic yield of 40% and 47% and genetics an additional 40% and 11% in the first and second trimesters respectively. Conclusion: Ultrasound is an effective screening but not a diagnostic tool. Complete characterizations of dysplasia increased from 22% by ultrasound alone to 86% with pathology and genetics.

The paired‐type homeodomain transcription factor Prrxl1 (also known as Drg11) is a key regulator of the differentiation and survival of dorsal root ganglia (DRG) and spinal nociceptive neurons in pre‐ and perinatal stages. Prrxl1^−/− mice exhibit abnormalities in DRG‐spinal projections, defects in superficial dorsal horn structure and neurochemistry, and reduced nociceptive behaviour in several pain tests. Although a low expression of Prrxl1 persists in dorsal root ganglia beyond embryonic development, no data exist on its role in adult life. In this paper we evaluate whether DRG expression of Prrxl1 is affected both in inflammatory and neuropathic models of pain in adult mice. Ipsilateral versus contralateral relative expression of Prrxl1 in the DRG was compared in control and pain animals. The expression of Prrxl1 mRNA in mice with zymosan‐induced peripheral inflammation presented a 3.06±0.71‐fold‐increase in ipsilateral ganglia, which was significantly different from the value observed in control animals. In contrast, a slight, non‐statistically significant decrease was detected in the SNI model of neuropathy. Interestingly, the expression of the mRNA splice variant Prrxl1b was unchanged in both pain conditions. Immunohistochemical studies showed an increase in the number of Prrxl1‐positive neurons in the inflammatory pain model, which belonged both in the peptidergic and non‐peptidergic categories. Our present results point to a role for Prrxl1 in sensitization of nociceptive neurons upon inflammatory pain.

Perception of noxious events relies on activation of complex central neuronal circuits. The spinal cord dorsal horn plays a pivotal role in the process relaying to the brain various types of somatosensory input. These functions are accomplished by distinct sensory neurons specifically organized in different laminae. They differentiate during development in a spatial‐temporal order due to the expression of combinatorial sets of homeodomain transcription factors. Here we demonstrate that the differential expression of the homeodomain transcription factors Prrxl1 (DRG11), Tlx3, and Lmx1b defines various subpopulations of spinal cord dorsal horn glutamatergic early born and late born neurons. Accordingly, in the superficial dorsal horn of Prrxl1^−/− mice, the number of glutamatergic neurons is reduced by 70%, while the number of Golgi‐impregnated and noxious‐induced Fos immunoreactive neurons is reduced by 85%. These results suggest a crucial role for Prrxl1 in the generation of various subpopulations of nociceptive glutamatergic superficial dorsal horn neurons. Developmental Dynamics 239:1684–1694, 2010.

Background Gene expression can be differentially regulated by alternatively spliced transcription factors, providing a mechanism for precise control of diverse morphogenetic events. The paired-type homedomain transcription factor Prrxl1 (formerly known as Drg11) was described as a key regulator of the differentiation of the spinal cord neuronal circuit dedicated to the processing of nociceptive information. Here, we report the characterization of a Prrxl1 alternative splice variant that we termed Prrxl1-b. Methods Mouse Prrxl1 isoform mRNA sequences were obtained by Rapid Amplification cDNA Ends (RACE) analysis. The distribution and the amount of Prrxl1-b at different developmental ages were analyzed by in situ hybridization and quantitative real-time PCR, and compared with those of Prrxl1. Results The amount of Prrxl1 was higher than that of the Prrxl1-b isoform both in the DRG and the spinal cord. Prrxl1-b contains the N-terminal homeodomain but differs from the previously identified Prrxl1 in the C-terminal part due to alternative mRNA processing. This results in the lack of the OAR domain in the Prrxl1-b primary structure. Prrxl1-b is exclusively localized in neurons primarily involved in the processing of the pain somatosensory modality. Prrxl1-b presents the same regional distribution pattern as Prrxl1, but differs as to the qualitative and quantitative expression profile at distinct developmental ages in the dorsal root ganglion and spinal cord. Conclusion We suggest that the tissue-specific role of the Prrxl1 gene may be sustained by an accurate balance in the ratio between the amount of Prrxl1 and its OAR-lacking variant, Prrxl1-b, which may be critical during nociceptive circuit development.

DRG11 is a paired domain transcription factor that is necessary for the assembly of the nociceptive circuitry in the spinal cord dorsal horn. It is expressed in small dorsal root ganglion (DRG) neurons and in their projection area in the spinal cord. Drg11 knockout mice exhibit structural and neurochemical defects both at the DRG and spinal superficial dorsal horn and present reduced nociceptive responses. In this study, a polyclonal antibody against DRG11 was generated and used for a detailed systematic spatio-temporal analysis of DRG11 expression during development. DRG11 is first detected at E10.5 in the spinal dorsal horn, DRG and trigeminal ganglion, where it persists until P14-21. At the cranial level, DRG11 expression is observed from E10.5 up to the same early post-natal ages in several cranial sensory ganglia and brain nuclei. These results suggest that DRG11 is required for the establishment of the first neuronal sensory relay along development. Developmental Dynamics 236:2653–2660, 2007.

Substantia gelatinosa (SG, lamina II) is a spinal cord region where most unmyelinated primary afferents terminate and the central nociceptive processing begins. It is formed by several distinct groups of interneurons whose functional properties and synaptic connections are poorly understood, in part, because recordings from synaptically coupled pairs of SG neurons are quite challenging due to a very low probability of finding connected cells. Here, we describe an efficient method for identifying synaptically coupled interneurons in rat spinal cord slices and characterizing their excitatory or inhibitory function. Using tight‐seal whole‐cell recordings and a cell‐attached stimulation technique, we routinely tested about 1500 SG interneurons, classifying 102 of them as monosynaptically connected to neurons in lamina I–III. Surprisingly, the vast majority of SG interneurons (n= 87) were excitatory and glutamatergic, while only 15 neurons were inhibitory. According to their intrinsic firing properties, these 102 SG neurons were also classified as tonic (n= 49), adapting (n= 17) or delayed‐firing neurons (n= 36). All but two tonic neurons and all adapting neurons were excitatory interneurons. Of 36 delayed‐firing neurons, 23 were excitatory and 13 were inhibitory. We conclude that sensory integration in the intrinsic SG neuronal network is dominated by excitatory interneurons. Such organization of neuronal circuitries in the spinal SG can be important for nociceptive encoding.