Involvement of the ventrolateral medulla in parkinsonism with autonomic failure

OBJECTIVE: To determine whether patients with PD and autonomic failure (AF), manifested primarily with orthostatic hypotension (OH), have a consistent loss of tyrosine hydroxylase (TH) neurons in the rostral ventrolateral medulla (RVLM), similar to that occurring in patients with multiple system atrophy (MSA) and AF, and to determine whether there is loss of nicotinamide, adenine dinucleotide phosphate (NADPH) diaphorase (NADPH-d) RVLM neurons in both groups of patients. METHODS: The numbers of TH and NADPH-d neurons in the RVLM was assessed in brain sections obtained at autopsy from five patients with suspected PD and OH, six patients with MSA, two patients with corticobasal ganglionic degeneration and no AF, and 10 control subjects with no history of neurologic disease. Cell numbers were compared among groups and correlated with their final neuropathologic diagnosis. RESULTS: The number of TH neurons in the RVLM of patients with PD and OH were not significantly different from control subjects, and there were marked individual variations. The TH cell numbers in the RVLM were significantly higher (p < 0.06) in patients with PD than in patients with MSA, despite a similar degree of severity of OH. As a group, patients with PD and OH had reduced numbers of NADPH-d cells in the RVLM compared with control subjects, but again there were marked individual variations. NADPH-d cell numbers were reduced consistently and more markedly in patients with MSA. CONCLUSION: Unlike the case in patients with MSA, the number of TH neurons in the RVLM is highly variable in patients with PD and is unlikely to contribute significantly to the pathophysiology of OH. As a group, patients with PD have reduced numbers of NADPH-d neurons in the RVLM, but some patients had cell counts similar to control subjects. On the other hand, NADPH-d cell depletion in the RVLM is a consistent finding in MSA and may contribute to cardiorespiratory dysfunction in this disorder.     

Nosocomial respiratory syncytial virus infection in Canadian pediatric hospitals: a Pediatric Investigators Collaborative Network on Infections in Canada Study

OBJECTIVE: To determine nosocomial transmission of respiratory syncytial virus (RSV) in Canadian pediatric hospitals, outcomes associated with nosocomial disease, and infection control practices. DESIGN: A prospective cohort study in the 1992 to 1994 winter respiratory seasons. SETTING: Nine Canadian pediatric university-affiliated hospitals. PARTICIPANTS: Hospitalized children with symptoms of lower respiratory tract infection (at least one of cough, wheezing, dyspnea, tachypnea, and apnea) and RSV antigen identified in a nasopharyngeal aspirate. RESULTS: Of 1516 children, 91 (6%) had nosocomial RSV (NRSV), defined as symptoms of lower respiratory tract infection and RSV antigen beginning >72 hours after admission. The nosocomial ratio (NRSV/[com-munity-acquired RSV {CARSV})] + NRSV) varied by site from 2.8% to 13%. The median length of stay attributable to RSV for community-acquired illness was 5 days, but 10 days for nosocomial illness. Four children with NRSV (4. 4%) died within 2 weeks of infection, compared with 6 (0.42%) with CARSV (relative risk = 10.4, 95% confidence interval: 3.0, 36.4). All sites isolated RSV-positive patients in single rooms or cohorted them. In a multivariate model, no particular isolation policy was associated with decreased nosocomial ratio, but gowning to enter the room was associated with increased risk of RSV transmission (incidence rate ratio 2.81; confidence interval: 1.65, 4.77). CONCLUSIONS: RSV transmission risk in Canadian pediatric hospitals is generally low. Although use of barrier methods varies, all sites cohort or isolate RSV-positive patients in single rooms. Children with risk factors for severe disease who acquire infection nosocomially have prolonged stays and excess mortality.     

Plasma cyclic nucleotide levels in acute leukemia patients

To verify the clinical usefulness of extracellular cyclic nucleotide determination as a tumor marker, plasma cyclic AMP (cAMP) and cyclic GMP (cGMP) levels were measured in 70 normal subjects and 173 acute leukemia patients studied in different stages of their disease. Mean plasma cAMP levels were similar in leukemic and normal subjects, although in 48 patients in the active stage of the disease, first diagnosis, or relapse, the cAMP values were below the normal range, and most of these patients failed to respond to chemotherapy. Plasma cGMP levels were markedly elevated in untreated patients, normalized in all patients who attained complete remission, and increased promptly to pretreatment values in patients who relapsed, suggesting that their determination may be useful to monitor the patients' response to treatment.     

Peripheral neuroimmune interactions: selected review and some clinical implications

Clinical Autonomic Research - To provide a brief and focused review on peripheral neuroimmune interactions and their implications for some clinical disorders. Narrative review of the literature...     

Parabrachial nucleus involvement in multiple system atrophy

Multiple system atrophy (MSA) is associated with respiratory dysfunction, including sleep apnea, respiratory dysrhythmia, and laryngeal stridor. Neurons of the parabrachial nucleus (PBN) control respiratory rhythmogenesis and airway resistance. Objectives: The objective of this study is to determine whether there was involvement of putative respiratory regions of the PBN in MSA. Methods: We examined the pons at autopsy in 10 cases with neuropathologically confirmed MSA and 8 age-matched controls. Sections obtained throughout the pons were processed for calcitonin-gene related peptide (CGRP) and Nissl staining to identify the lateral crescent of the lateral PBN (LPB) and the Kölliker-Fuse nucleus (K-F), which are involved in respiratory control. Cell counts were performed using stereology. Results: There was loss of CGRP neurons in the PBN in MSA (total estimated cell counts for the external LPB cluster was 12,584 ± 1146 in controls and 5917 ± 389 in MSA, p < 0.0001); for the external medial PBN (MPB) cluster it was 15,081 ± 1758 in controls and 7842 ± 466 in MSA, p < 0.001. There was also neuronal loss in putative respiratory regions of the PBN, including the lateral crescent of the LPB (13,039 ± 1326 in controls and 4164 ± 872 in MSA, p < 0.0001); and K-F (5120 ± 495 in controls and 999 ± 308 in MSA, p < 0.0001). Conclusions: There is involvement of both CGRP and putative respiratory cell groups in the PBN in MSA. Whereas the clinical implications of CGRP cell loss are still undetermined, involvement of the LPB and K-F may contribute to respiratory dysfunction in this disorder.     

Risk factors associated with having psoriatic arthritis in patients with cutaneous psoriasis

The aim of this study was to determine if the following characteristics were associated with the presence of psoriatic arthritis in a sample of psoriasis patients: race, family history of psoriasis and psoriatic arthritis, age of onset of psoriasis, smoking, alcohol consumption and the maximum body surface area (BSA) affected by psoriasis. This was a case–control study involving 400 psoriasis patients who attended the Psoriasis and Photo‐medicine clinic in the National Skin Center of Singapore over a 1‐year period. Cases were psoriasis patients with psoriatic arthritis while controls were psoriasis patients without psoriatic arthritis. The diagnosis of psoriatic arthritis was made by rheumatologists and participants completed a self‐administered standardized questionnaire. The maximum BSA involved was determined from the case notes. Psoriatic arthritis was not significantly associated with sex, race, age of onset of psoriasis, a family history of psoriasis, smoking and alcohol consumption but was significantly associated with a family history of psoriatic arthritis (P < 0.001) and the maximum body surface involved (P = 0.05). Using multivariate analysis to control for variables, the presence of psoriatic arthritis was significantly associated with a family history of psoriatic arthritis (odds ratio [OR] = 20.5; 95% confidence interval [CI] = 2.49–169.10) and the maximum BSA involved (OR = 2.52; 95% CI = 1.33–4.75). Indian psoriatic patients were more likely to have psoriatic arthritis compared to the other races. A family history of psoriatic arthritis and a greater maximum body surface involved may be associated with having psoriatic arthritis in this study population of psoriasis patients.     

Organization of NADPH-diaphorase-reactive neurons and catecholaminergic fibers in human intermediolateral cell column

We studied the distribution of NADPH-d-reactive sympathetic preganglionic neurons (SPNs) and tyrosine hydroxylase (TH) immunoreactive fibers at T1, T4, T8, and T10 of human thoracic cord. NADPH-d-reactive SPNs were present at all segments. TH-immunoreactive fibers were distributed within the NADPH-d neuropil and appeared to contact SPNs. These interactions may be important for normal and pathological control of arterial pressure.