Identification of cathepsin C mutations in ethnically diverse papillon-Lefèvre syndrome patients.

INTRODUCTION: Papillon-Lefèvre syndrome (PLS) is an autosomal recessive disorder characterised by palmoplantar keratoderma and severe, early onset periodontitis, which results from deficiency of cathepsin C activity secondary to mutations in the cathepsin C gene. To date, 13 different cathepsin C mutations have been reported in PLS patients, all of which are homozygous for a given mutation, reflecting consanguinity. AIM: To evaluate the generality of cathepsin C mutations in PLS, we studied an ethnically diverse group of 20 unrelated families. METHODS: Mutations were identified by direct automated sequencing of genomic DNA amplified for exonic regions and associated splice site junctions of the cathepsin C gene. Long range PCR was performed to determine the genomic structure of the cathepsin C gene. RESULTS: The cathepsin C gene spans over 46 kb, with six introns ranging in size from 1.6 to 22.4 kb. Eleven novel mutations and four previously reported mutations were identified in affected subjects from 14 families. Missense mutations were most common (9/15), followed by nonsense mutations (3/15), insertions (2/15), and deletions (1/15). Among these 14 probands, two were compound heterozygotes. Affected subjects with transgressions of the dermal lesions onto the knees or elbows or both had mutations in both the pro- and mature regions of the enzyme, although most were in the mature region. CONCLUSION: Mutations in the mature region of cathepsin C were more likely to be associated with the transgressions of the dermatological lesions, although the results were not statistically significant. A comprehensive list of all cathepsin C mutations described to date, representing 25 mutations from 32 families with PLS and related conditions, is also presented.

Paecilomyces varioti endocarditis on a prosthetic aortic valve.

Fungal endocarditis following prosthetic valve surgery has assumed increased importance as a cause of postoperative death. We present, to our knowledge, the first case of the fungus Paecilomyces varioti producing endocarditis on a prosthetic aortic valve. This seems to be an extremely indolent organism which exhibits an apparent response to antibiotic therapyl. In vitro evidence suggests that this fungus is sensitive to attainable serum levels of both 5-fluorocytosine and amphotericin B. However, after viewing the extracted valve and the devastating embolic phenomenon in our patient, we believe that medical therapy alone would not suffice. Thus we suggest that prompt valve replacement be performed in future cases.

Electrical basis for the effects of ethyl alcohol on canine gastric corpus muscles.

The effects of ethyl alcohol (EtOH) on membrane potential and slow wave activity were tested in strips of canine corpus circular muscle. Previous studies have shown that EtOH (0.1-1%) reduced the force and frequency of phasic contractions of corpus muscles and increased tone. It was the intention of this study to determine whether the mechanical effects were due to an electrical mechanism. Intracellular recordings revealed that EtOH hyperpolarized resting membrane potential and reduced the amplitude, duration and frequency of slow waves. These changes were concentration-dependent over the same range of EtOH concentrations that inhibited phasic mechanism activity. Simultaneous recordings of force and membrane potential demonstrated these effects. The tone produced by corpus muscles exposed to EtOH could not be explained by an electrical mechanism. The fact that membrane potential and several parameters of the slow wave depolarization are affected by EtOH might be explained by an increase in membrane conductance produced by EtOH.

High-dose intravenous pulse methylprednisolone hemisuccinate in acute Behçet retinitis.

PURPOSE: To report the response of acute Behçet retinitis to high-dose corticosteroids. METHOD: Case report. A 58-year-old man with Behçet disease and severe bilateral glaucoma experienced a sudden decrease of visual acuity to counting fingers in his (better-seeing) left eye. Examination disclosed hypopyon uveitis and an infiltrative retinitis threatening the fovea. He received intravenous methylprednisolone hemisuccinate, 1 gram per hour on each of 3 successive days, followed by oral prednisone and cyclosporine. RESULTS: The retinal infiltrate disappeared within 24 hours. Visual acuity improved to LE, 20/400 by day 5 and returned to LE, 20/30 after 3 months. A visual field demonstrated a scotoma corresponding to the location of the previous retinitis. CONCLUSION: High-dose intravenous methylprednisolone can reverse severe vision loss in acute Behçet retinitis.

Regression of cytomegalovirus retinitis associated with protease-inhibitor treatment in patients with AIDS.

PURPOSE: To report the observation that anti-retroviral therapy that includes a protease inhibitor can induce the regression of cytomegalovirus retinitis without requiring specific anticytomegalovirus drug therapy. METHODS: We examined the fundi of four patients with advanced acquired immunodeficiency syndrome (AIDS) who were placed on highly active antiretroviral therapy consisting of two nucleoside analogs and a protease inhibitor. The combined medications resulted in increased CD4+ T-lymphocyte counts and decreased load of human immunodeficiency virus (HIV-1). A prospective evaluation of the effect of these medications on an active cytomegalovirus retinitis lesion was conducted in one patient. Retinal lesions were documented with fundus photography. RESULTS: None of these patients received specific anticytomegalovirus medications. The average baseline CD4+ T-lymphocyte count was 33 cells per microliter (range, 4 to 88 cells per microliter) and increased an average of 118.5 cells per microliter (range, 66 to 185 cells per microliter). Average baseline plasma HIV-1 viral loads (HIV-1-RNA copies per ml) decreased 1.46 log units (range, 0.65 to 2.93 log units). In one patient, posterior progression (border advancement toward the posterior pole) of a cytomegalovirus retinitis lesion decelerated over time and stopped. Three other patients on initial examination had areas of retinal scarring consistent with healed cytomegalovirus retinitis. CONCLUSIONS: The addition of an HIV-1 protease inhibitor in the treatment of AIDS may lead to complete regression of cytomegalovirus retinitis without specific anticytomegalovirus medications. This effect may be related to reduced HIV-1 loads, a possible direct drug effect, an increase in CD4+ T-lymphocyte counts, or other associated changes in immune status.

Bartonella henselae infection associated with peripapillary angioma, branch retinal artery occlusion, and severe vision loss.

PURPOSE: To report atypical clinical features of Bartonella henselae neuroretinitis treated with combination antibiotics. METHOD: Case report. RESULTS: A 20-year-old man with a positive B. henselae titer developed a unilateral neuroretinitis, a large peripapillary angiomatous lesion, branch artery occlusion with ischemic maculopathy, and vision loss that failed to improve with clindamycin. Treatment with doxycycline and rifampin led to rapid clinical improvement. The severe vision loss in this case is atypical. CONCLUSIONS: Ocular findings associated with B. henselae infection may include retinal angiomatous lesion and branch retinal artery occlusion. Doxycycline and rifampin were successful in treating the infection.

Default in the outpatient treatment of tuberculosis in two hospitals in Northern India.

STUDY OBJECTIVE: The purpose of the study was to examine default rates in tuberculosis treatment in two hospitals in north India with different follow up arrangements. DESIGN: The study was a retrospective cohort study. SETTING: Two hospitals were involved. One was the District Tuberculosis Centre for the Kulu Valley area of Himachal Pradesh. The other was a private mission hospital serving the same area. PATIENTS: The study involved 321 patients at the tuberculosis centre and 381 at the mission hospital, being all those newly diagnosed with tuberculosis from October 1982 to September 1983; follow-up to October 1984. Patients at the mission hospital were more affluent and had travelled much further to seek treatment; only one reminder was sent to defaulters from treatment. The government hospital had a more active response if the patients missed an appointment, with a home visit by a health worker. RESULTS: Rates of permanent default were similar in each hospital and were very high: approximately 40% at 6 months, 60% at 12 months, and 65% at 18 months of treatment. CONCLUSIONS: Default was a major problem irrespective of the follow up procedures employed. Recommendations are made concerning treatment and follow up, including better communication about the disease and its treatment, active follow up of defaulters, and review of treatment policies.

CMV retinitis and the controversies associated with highly active antiretroviral therapy and the immune recovery hypothesis.

The aggressive multidrug regimen of highly active antiretroviral therapy (HAART) has offered some degree of promise of immune reconstitution in AIDS patients, a phenomenon that theoretically would impact positively on the incidence and severity of opportunistic infections. Some studies already have noted complete regression of cytomegalovirus (CMV) retinitis without specific use of anti-CMV agents in patients undergoing HAART. However, the role of HAART in CMV retinitis remains controversial among investigators. This review of the salient details regarding the controversies associated with CMV retinitis and the immune recovery hypothesis is meant to shed light on current and future therapeutic issues concerns. Early data seem to predict a decline in CMV retinitis. However, some investigators have noted that increased CD4 T-lymphocyte counts may not protect against CMV retinitis; therefore, the diagnosis cannot be excluded based on count alone. There is also the question of whether CMV retinitis progression in any way represents failure of HAART in those patients receiving this type of combination therapy. HAART is seen as an encouraging development in the treatment of AIDS and opportunistic infection, but its more specific therapeutic effect on CMV retinitis requires further research with controlled prospective clinical trials.

Effect of highly active antiretroviral therapy on the incidence of HIV-related cytomegalovirus retinitis and retinal detachment.

Cytomegalovirus retinitis (CMVR) is the most common intraocular infection encountered in ophthalmic practices. To assess the impact of highly active antiretroviral therapy (HAART) on the incidence of CMVR and subsequent retinal detachments, a retrospective review of the HIV+ patients seen at a single university and community-based practice between 1992-1993 (group 1), before the advent of protease inhibitors, was compared with the data obtained from October 1996 to October 1997 (group 2) and October 1997-1998 (group 3), after the widespread use of HAART. The incidence of CMVR and retinal detachment rates for each group was calculated and compared. Twenty five (2.6%) of 974 HIV+ patients in group 1 developed CMVR. Of these, four patients developed retinal detachment (16%). Group 2 had a total of 1084 HIV+ patients, 18 (1.7%) of whom developed CMVR, which indicates a 35% decline of the incidence of CMV retinitis at our institution (p = 0.052, Odds ratio = 0.533, Confidence interval 0.28-1.01) and three patients (20%) developed retinal detachment. Only 1 patient (0.07%) of 1274 patients in group 3 developed CMVR, which represents a 99% reduction since 1993 (p = 0.0000000456). We conclude that the incidence of CMVR at this institution has decreased significantly with the recent use of HAART therapy. This effect may be related to the aggressive use of HAART and associated immune recovery in this population of AIDS patients. In this small series, however, the rate of retinal detachment appeared unchanged, but was only observed in those individuals who were not on HAART or who had just recently started.

Haemorrhagic syndrome of cattle of suspected mycotoxic origin.

An outbreak of disease characterised by haemorrhages, anaemia, leucopenia, thrombocytopenia, skin lesions, degenerative and inflammatory tissue changes and death was investigated in herd of dairy cows. A tentative diagnosis based on circumstantial evidence was of mycotoxicosis arising from the feeding of mouldy barley.

Incidence of contralateral occult inguinal hernia found at the time of laparoscopic trans-abdominal pre-peritoneal (TAPP) repair.

BACKGROUND: Trans-abdominal laparoscopic inguinal hernia repair allows rapid assessment and exploration of the contralateral groin and repair of an occult hernia. Although previous studies have shown that the totally extra-peritoneal (TEP) hernia repair can be used to assess the contralateral groin, there is little data pertaining to the trans-abdominal pre-peritoneal (TAPP) approach. The aim of this study was to document the incidence of occult contralateral hernia at the time of TAPP hernia repair. METHODS: Data were collected prospectively from all patients undergoing laparoscopic TAPP hernia repair in a District General Hospital over a three-year period. Two specialist laparoscopic/upper gastrointestinal surgeons undertook all of the operations and telephone follow-up was carried out by a dedicated laparoscopic specialist nurse. RESULTS: A total of 310 patients underwent hernia surgery. Four cases were excluded, leaving 306 patients in the study. The male:female ratio was 10.5:1, with a median age of 59 years. Two hundred and six (67%) patients were booked for a unilateral hernia repair; of these, a contralateral hernia was found and repaired in 45 (22%). In 76 cases where a bilateral repair was planned, 61 (80%) went on to have both groin defects repaired. In the remaining 20%, the clinical suspicion of bilateral hernia was revised at the time of surgery to unilateral only. Twenty (7%) patients were booked to undergo a unilateral repair with the possibility of a contralateral hernia--in this group, the suspected contralateral defect was confirmed in 6 (30%) cases. Four (1%) cases were booked as femoral repairs, one of which was found to be an inguinal hernia. The clinical diagnostic accuracy was 78%. CONCLUSION: Accurate incidence figures of an occult contralateral inguinal hernia will enhance the pre-operative information given to patients and may impact on resource allocation and planning theatre logistics. Finding and repairing an occult contralateral hernia at the time of TAPP has the distinct advantage that it saves the patient from further symptoms and from another operation with its associated potential morbidity.

Emergency laparoscopic cholecystectomy in an unselected cohort: a safe and viable option in a specialist centre.

INTRODUCTION: Patients presenting acutely with symptomatic gallstone-related disease have historically had their laparoscopic cholecystectomy (LC) deferred due to perceived increased operative risks in the acute setting, particularly conversion to open surgery. The aim of this study was to compare morbidity and mortality between unselected cohorts of patients undergoing elective and 'emergency' LC in a District General Hospital. METHODS: All gallstone-related elective and emergency admissions under the care of two specialist laparoscopic surgeons during a two-year period were included. Patients admitted acutely with a diagnosis of biliary colic, acute cholecystitis or gallstone pancreatitis underwent 'emergency' LC during the same admission. Data were collected prospectively on patient demographics, inpatient stay, post-operative course and POSSUM scores. RESULTS: 423 patients underwent LC, of which 301 (71.1%) were elective and 122 (28.9%) were 'emergency' procedures. ASA grades and POSSUM physiologic scores were similar between the two groups. The overall morbidity rates were similar in the emergency and elective groups (13.1% vs. 7.3%, p = 0.088), and there was no significant difference in the rates of major complications including conversion to open surgery (0% vs. 0.3%, NS), bile leak or re-operation between the two groups. 30-day mortality rates were similar in the two groups (0.8% vs. 0%, NS). CONCLUSION: When performed by specialist laparoscopic surgeons, LC in the acute setting is safe with mortality and morbidity rates, including conversion to open surgery, comparable to elective LC.

Effects of membrane potential on electrical slow waves of canine proximal colon.

The effects of membrane potential on the waveforms and propagation of slow waves were tested using circular muscles of the canine colon. Studies were conducted with intracellular recording techniques on cross-sectional strips of canine proximal colon. Circular muscle cells near the submucosa generated slow waves that decayed in amplitude as they spread through the circular layer. The membrane potentials of cells were less negative as a function of distance from the submucosal border. Cells near the submucosa were depolarized with elevated external K+ and electrical pulses using the partitioned chamber technique. The waveforms of depolarized submucosal cells were compared with events recorded from cells in the bulk of the circular layer. The waveform changes caused by experimental depolarization were different from the changes in waveform that occur during propagation, suggesting the latter are due to a different mechanism than depolarization. The effects of the membrane potential on syncytial input resistance and length constant were also evaluated. The results of these studies are consistent with the hypothesis that slow-wave propagation across the circular layer in canine proximal colon occurs passively.

Origin and propagation of electrical slow waves in circular muscle of canine proximal colon.

Experiments to determine the site of slow-wave origin and the mechanism of propagation were performed on muscles of the canine proximal colon. Cells along the submucosal border of the circular layer had resting membrane potentials (RMP) averaging -78 mV, and slow waves, 40 mV in amplitude. The RMP of cells through the thickness of the circular layer decreased exponentially with distance from the submucosal border, such that RMPs of circular cells at the myenteric border were only -43 mV. Slow waves decreased in amplitude through the thickness such that slow waves could not be detected adjacent to the myenteric border. When a thin strip of muscle along the submucosal border was removed, slow waves were not recorded from the bulk of the circular layer and could not be evoked by acetylcholine. Slow waves were still present in the excised strip. Experiments to determine the rate of slow-wave propagation were also performed. Two cells were impaled, one at the submucosal surface, and another at some distance through the circular layer. Slow waves occurred nearly simultaneously at both sites. What latency was observed could be explained on the basis of electrotonic conduction. The results support the hypothesis that in the canine proximal colon slow waves are generated at the extreme submucosal surface of the circular layer. The bulk of the circular layer does not possess either pacemaker or regenerative mechanisms, and slow waves propagate passively toward the myenteric border. The cable properties of the circular muscle syncytium furnish a barrier to invasion of the longitudinal layer by the slow wave event.

Interaction of two electrical pacemakers in muscularis of canine proximal colon.

Experiments were performed to determine the source of the 20 cycles/min electrical oscillation commonly seen in colonic electrical records, the influence of the 20 cycles/min rhythm on the circular and longitudinal muscle layers, and the interactions between the 20 cycles/min rhythm and slow waves in circular muscle cells. Cross-sectional muscle preparations of the canine proximal colon were used to allow impalement of cells at any point through the thickness of the muscularis. Intracellular recordings from circular muscle cells clearly showed the two characteristic pacemaker frequencies in the colon (6 cycles/min slow waves; 20 cycles/min oscillations). The 20 cycles/min oscillations were recorded from longitudinal and circular muscle cells. Their amplitudes were greatest at the myenteric border. In the longitudinal layer the 20 cycles/min events initiated action potentials; in circular muscle the 20 cycles/min events summed with slow waves. Simultaneous recordings from circular and longitudinal cells across the myenteric border demonstrated that events in the two layers were usually in phase, suggesting that the two layers are electrically coupled and are paced by a common pacemaker. The amplitude of the 20 cycles/min events decayed with distance from the myenteric border in both circular and longitudinal muscles. The data demonstrate that two discrete populations of pacemaker cells generate the spontaneous electrical activity in the colon. Both events appear to passively spread through the circular muscle. It is the summation of these events that appears to serve as the signal for excitation-contraction coupling in circular muscle.

Electrical pacemakers of canine proximal colon are functionally innervated by inhibitory motor neurons.

Pacemaker activity in the canine proximal colon occurs at the submucosal and myenteric borders of the circular layer [Am. J. Physiol. 252 (Cell Physiol. 21): C215-C224 and C290-C299, 1987]. The present study investigated the neural regulation of rhythmic electrical activity. Spontaneous inhibitory junction potentials (IJPs) were observed in intracellular recordings from circular muscle cells near the myenteric border. The amplitudes of these events decayed with distance through the circular layer. Stimulation at the myenteric plexus surface evoked IJPs that mimicked the spontaneous events. Stimulation at the submucosal surface evoked IJPs in adjacent cells that were of shorter duration and of different waveform than myenteric IJPs. Amplitudes of IJPs evoked by stimulation near either surface decayed with distance from the site of stimulation. The decay functions for IJPs were essentially identical to the decay of spontaneous slow waves or myenteric potential oscillations. Spontaneous and evoked IJPs affected the amplitudes, durations, and patterns of ongoing rhythmic electrical activity. The data suggest that myenteric and submucosal pacemaker populations may be innervated by different populations of inhibitory nerve fibers. Innervation appears to be heterogeneous with dense populations of inhibitory nerve fibers predominantly located in the pacemaker regions. Neural regulations of pacemaker activity influences rhythmic electrical activity throughout the muscularis.

Role of sodium pump in membrane potential gradient of canine proximal colon.

A large gradient in membrane potential exists through the thickness of the circular layer in canine colonic muscles. This study tested the effects of several experimental manipulations known to block electrogenic sodium pumping on the resting potentials of colonic muscles. Membrane potentials were recorded with microelectrodes from cells through the circular muscle layer. In cells adjacent to the submucosal surface of the circular layer, application of ouabain (10(-6) to 10(-5) M) caused an average membrane depolarization of 36 mV. Removal of the external K+ resulted in depolarizations similar to the effect of ouabain. Readmission of K+ (5.9 mM) produced repolarization and an additional hyperpolarization that averaged 13 mV beyond the resting potential. When exposed to 15 mM K+, cells hyperpolarized well beyond the estimated potassium equilibrium potential (EK). Ouabain blocked the repolarization in response to reintroduction of external K+. Lowering the bath temperature to 20 degrees C rapidly depolarized membrane potential; rewarming repolarized cells. Ouabain and K+-free solutions blocked the repolarization response to rewarming. Cells also depolarized when exposed to solutions in which the NaCl was replaced with LiCl. Membrane potentials of cells within the bulk of the circular layer decreased as a function of distance from the submucosal border. Cells at the myenteric border of the circular muscle were not significantly affected by ouabain and K+-free solution, but these treatments abolished the gradient in membrane potential across the circular layer.(ABSTRACT TRUNCATED AT 250 WORDS)