Closed mitral valvotomy for mitral restenosis: experience in 113 consecutive cases

The costs of heart operations and the problems related to anticoagulation after prosthetic valve replacement are among the limitations faced by patients in nonindustrialized countries with mitral stenosis caused by chronic rheumatic heart disease. The young age at which these patients are seen also compels the surgeon to preserve the native valve. The least costly and optimal way to achieve this objective is by closed mitral valvotomy. After closed mitral valvotomy, mitral restenosis is commonly encountered. We report here our 10-year experience with operation on 113 consecutive patients with mitral restenosis. Closed transventricular revalvotomy was performed with Tubbs dilator in 105 of 113 patients. Mean age was 343 years, with a male to female ratio of 1:1.5. Most patients were in New York Heart Association functional classes III and IV (74.3% and 19.4%, respectively). Mean interval between first and second valvotomy was 9.4 years, Hospital mortality rate was 2.8%, trivial postoperative mitral regurgitation occurred in 16.1%, and moderately severe regurgitation occurred in 1.9%. Early postoperative systemic embolism occurred in 3.8% of the cases. Moderate to excellent symptomatic improvement was noted in 89.4% of the cases and poor results were seen in 10.2%. Late follow-up of 76 patients ranged from 2 to 10 years (mean 3.8 years), with 39.4% patients in New York Heart Association class I and 50% in class II. Close mitral revalvotomy is thus an economical, simple, and safe palliative procedure that carries good long-term results.

Antifungal susceptibility pattern of non-albicans Candida species & distribution of species isolated from Candidaemia cases over a 5 year period

A marked increase in the incidence of patients of candidaemia is reported from a tertiary care hospital in north India over the last five years (15 patients in 1991 and 275 in 1995). The distribution of Candida species isolated from January 1991 through December 1995 was investigated. Antifungal susceptibility against amphotericin B, 5-fluorocytosine, ketoconazole and fluconazole of 100 randomly selected non-albicans Candida species isolated during 1995 was determined by an in-house standardized disc diffusion method and the standard broth dilution procedure recommended by the National Committee for Clinical Laboratory Standards (NCCLS, USA). The disc diffusion method correlated well with NCCLS method except for ketoconazole. Resistance against any antifungal was confirmed only by results of NCCLS method. A shift to higher isolation of non-albicans Candida species was observed during this period (52.6% in 1992 to 89.5% in 1995). Resistance was observed against 5-fluorocytosine in 3 per cent strains of C. krusei; and against fluconazole in 24.2 per cent of C. krusei, 15.4 per cent of C. guilliermondii and 5.7 per cent strains of C. tropicalis. No resistance was detected against amphotericin B and ketoconazole. Thus Candida species with fluconazole resistance have become more prominent in recent years.

Introducing stress management into general practice

The biomedical model that forms the basis of conventional medical practice is limited in its usefulness when applied to many of the presentations encountered in clinical general practice. Anxiety as a presenting symptom on its own is the fifth commonest presentation in Australian general practice. To relieve the physical symptoms is merely the first step; teaching the patient to manage the accompanying dys-stress more effectively must be an important part of our duty of care. The skills thus acquired will equip the patient to cope better with the present and subsequent health crises. A few simple exercises that I have found useful both for myself and for my patients are described. These exercises can be easily integrated into clinical practice.

Patient satisfaction at health centres in Trinidad and Tobago

The aim of this paper is to identify background characteristics of health centre users in Trinidad and Tobago and their perceptions of the services provided. Multi-staged sampling was used to select 1,500 health centre users throughout the country. Data were obtained using structured interviews conducted on regular clinic days. Results show that there is an overwhelmingly large percentage of unemployed persons (80.4%) and women (75.9%) among the users of health centres. The elderly is well represented, with 25.4 percent of the sample being over 60 years of age. Also, occupational status of family wage earners and educational attainment levels of respondents reflect a disproportionately higher number from lower socio-economic groupings among health centre users. On the other hand, proportions of different ethnic and religious groups among the respondents bear a striking similarity to the general population of Trinidad and Tobago. Respondents appear to be generally satisfied with the services of the health centres. When the categories for "satisfied' and "very satisfied' were combined, results show that 73.0% of respondents were satisfied with the comfort of the health centre, 81.7% with the ease and convenience of getting to the health centre and 67.4% with the medical care received at the health centre. According to respondents' opinions, the services in greatest need of improvement are the pharmacy and doctor services, especially through reducing the long waiting period. When the doctors, nurses and pharmacists were compared with respect to "courtesy and consideration', "Skills and Competence' and "advice provided', results show that the generally high levels of satisfaction are remarkably similar in all three cases.

Beta 2-adrenergic function in cultured rat proximal tubule epithelial cells

We conducted studies to determine whether functional beta 2-adrenoceptors are present in cultured rat proximal tubule epithelial cells. To determine whether cultured cells maintain polarity with respect to sodium transport, cells were acid loaded. Acid loading resulted in stimulation of sodium transport. Exposure of acid-loaded cells to alkaline extracellular pH further enhanced sodium transport (22Na flux at pH 7.50 was 68.1 +/- 44% above pH 7.00, P < 0.05). Cultured proximal tubules also exhibited basolateral 86Rb uptake, 65% of which was ouabain sensitive. Thus cultured cells maintain apical Na/H antiport and basolateral Na-K-adenosinetriphosphatase (Na-K-ATPase). Metaproterenol (10(-6) M), a selective beta 2-agonist, stimulated Na-K-ATPase activity by 36 +/- 6% above control (P < 0.05). The stimulatory effect was blocked by ICI-118551, a selective beta 2-antagonist. To determine whether metaproterenol-dependent increases in Na-K-ATPase were dependent on apical sodium entry, apical entry was blocked with dimethylamiloride or maximized with monensin. Both dimethylamiloride and monensin prevented metaproterenol activation of Na-K-ATPase. Metaproterenol-mediated increases in Na-K-ATPase activity were associated with increases in sodium transport (27 +/- 10% above control, P < 0.05), which was prevented by dimethylamiloride. In contrast to isoproterenol, metaproterenol did not stimulate cAMP production. In summary, we have shown that functional beta 2-adrenoceptors are present on cultured rat proximal tubules. beta 2-Adrenoceptor activation results in increases in Na-K-ATPase and Na transport as a consequence of increased apical sodium entry.

Complications of treadmill testing

Complications occurring in 2,400 treadmill tests are reported, out of which 2107 (87.8%) were on males and 292 (12.2%) on females. The total number of patients with complications was 29 (1.2%) and the types were: acute MI in 2, ventricular tachycardia (sustained) in 3, nonsustained in 7 with ventricular couplets in 3 patients, atrial tachyarrhythmias in four of AVNRT in 2, EAT in 2, SVT with abberancy in 1, SVT (undifferentiated) in 3, bradyarrhythmias in form of sinus bradycardia in 4, hypotension in 4 and AV block in 2. There were no deaths. Only 8 (0.33%) patients required treatment-2 each of acute MI, sustained VT, AVNRT and hypotension, though only 4 of them were hospitalised (2 each of acute MI and VT) and subsequently discharged. Highest incidence of complications was seen in post MI patients (2.01%) followed by those with typical anginal pain (1.9%) and they had more serious problems in form of MI and sustained VT. 55.17% patients with complications were positive for provocative ischaemia as compared to 22.75% positivity in the total. Although 14 (38.2%) patients developed complications at workload of 4-6 METS but 2 achieved load of 10 METS also. Complications were seen mostly during exercise and also during recovery only.

Gene targeting reveals a hierarchy of transcription factors regulating specification of lymphoid cell fates

Specification of B- and T-lymphoid cell fates appears to involve the expression of a shared set of genes encoding recombination proteins and of genes encoding lineage-specific components of antigen receptors. Recent studies using gene targeting have identified transcription factors that are required for the proper specification of lymphoid cell fates. On the basis of these data, a regulatory gene hierarchy which orchestrates the development of lymphoid progenitors from hematopoietic stem cells can be proposed.

Electroencephalogram bispectral analysis predicts the depth of midazolam-induced sedation

BACKGROUND

The electroencephalogram (EEG) has been used to study the effects of anesthetic and analgesic drugs on central nervous system function. A prospective study was designed to evaluate the accuracy of various EEG parameters for assessing midazolam-induced sedation during regional anesthesia.

METHODS

Twenty-six consenting adult patients were administered 4.5-20 mg intravenous midazolam (in increments of 0.5-1 mg bolus doses every 6-10 min) until they became unresponsive to tactile stimulation (i.e., mild prodding or shaking). The EEG was continuously recorded from a bifrontal montage (FP1-Cz and FP2-Cz) to obtain the bispectral index (BI), 95% spectral edge frequency (SEF), median frequency (MF), and delta, theta, alpha, and beta power bands. Sedation was assessed clinically at 6-10-min intervals using the Observers' Assessment of Alertness/Sedation (OAA/S) scale, with 1 = no response (unconsciousness) to tactile stimulation to 5 = wide awake. The EEG parameters were correlated with the OAA/S scores using nonparametric Spearman's rank-correlation analysis. Kruskal-Wallis analysis of variance was used to determine significant changes in EEG parameters during the onset of and recovery from midazolam-induced sedation.

RESULTS

Of the EEG parameters studied, the BI exhibited the best correlation with OAA/S scores during both the onset (Spearman's Rho = 0.815) and recovery (Spearman's Rho = 0.596) phases. With increasing sedation, there was a progressive decrease in the BI (OAA/S score of 5: BI = 95.4 +/- 2.3; 4: 90.3 +/- 4.5; 3:86.6 +/- 4.6; 2:75.6 +/- 9.7; 1:69.2 +/- 13.9). A similar pattern was found for the 95% SEF as the OAA/S score decreased from 4 to 1. Similarly, EEG-BI increased with recovery from the sedative effects of midazolam (OAA/S score = 2:BI = 75.2 +/- 10.2; 3:82.3 +/- 7.3; 4:90.8 +/- 6). However, no consistent changes were found with the other EEG parameters. The mean EEG values between OAA/S scores 3 and 2 and between OAA/S scores 2 and 1 during the onset and recovery phases from midazolam-induced sedation, defined as EEG50 values for response to verbal command (EEG50-VC) and to shaking of the head (EEG50-SH), were 79.3 +/- 8 and 70.8 +/- 14.3, respectively, for EEG-BI. The EEG-BI displayed the smallest coefficients of variation for the EEG50-VC and EEG50-SH values.

CONCLUSIONS

The EEG-BI appears to be a useful parameter for assessing midazolam-induced sedation and can predict the likelihood of a patient responding to verbal commands or to shaking of the head during midazolam-induced sedation.

PU. 1 is not essential for early myeloid gene expression but is required for terminal myeloid differentiation

We have previously shown using gene targeting that PU.1 is essential for the development of lymphoid and myeloid lineages during fetal liver hematopoiesis. We now show that PU.1 is required for the maturation of yolk sac-derived myeloid progenitors and for the differentiation of ES cells into macrophages. The role of PU.1 in regulating target genes, thought to be critical in the development of monocytes and granulocytes, has been analyzed. Early genes such as GM-CSFR, G-CSFR, and myeloperoxidase are expressed in PU.1-/- embryos and differentiated PU.1-/- ES cells. However, the expression of genes associated with terminal myeloid differentiation (CD11b, CD64, and M-CSFR) is eliminated in differentiated PU.1-/- ES cells. Development of macrophages is restored with the introduction of a PU.1 cDNA regulated by its own promoter. The PU.1-/- ES cells represent an important model for analyzing myeloid cell development.

Intrathecal fentanyl prolongs sensory bupivacaine spinal block

The purpose of investigation was to study the effect of intrathecal fentanyl on the onset and duration of hyperbaric bupivacaine-induced spinal block in adult male patients. Forty-three patients undergoing lower extremity or genitourinary surgery were enrolled to receive either 13.5 mg hyperbaric bupivacaine 0.75% + 0.5 ml CSF it, (Group I) or 13.5 mg hyperbaric bupivacaine 0.75% + 25 micrograms fentanyl it, (Group II) according to a randomized assessor-blind protocol. The onset and duration of sensory block were assessed by pinching the skin with forceps in the midclavicular line bilaterally every two minutes for first twenty minutes and then every five to ten minutes. Similarly, the onset and duration of motor block were assessed and graded at the same time intervals using the criteria described by Bromage. The time required for two sensory segment regression and sensory regression to L1 dermatome was 74 +/- 18 and 110 +/- 33 min vs 93 +/- 22 and 141 +/- 37 min in Groups I and II, respectively (P < 0.05). Intrathecal fentanyl did not enhance the onset of sensory or motor block, or prolong the duration of bupivacaine-induced motor spinal block. Fewer patients demanded pain relief in the fentanyl-treated group than in the control group in the early postoperative period (19% vs 59%; P < 0.05). Episodes of hypotension were more frequent in the fentanyl-treated group than in the control group (43% vs 14%; P < 0.05). We conclude that fentanyl, 25 micrograms it, prolonged the duration of bupivacaine-induced sensory block (sensory regression to L1 dermatone) by 28% and reduced the analgesic requirement in the early postoperative period following bupivacaine spinal block.

Tuberculous arthritis of the knee--an unusual presentation

A 54 year old male who had an unusual clinical manifestation and radiological features proven to have tuberculosis arthritis of the knee on synovial biopsy is presented here.

Physico-chemical properties of brain cathepsin H

Cathepsin H (EC 3.4.22.16) from cow brain, purified to approximately 1800-fold with approximately 26% activity yield, hydrolysed BANA, Leu-2-NNap, Arg-2-NNap, and Met-2-NNap maximally at pH 6.5, 6.8, 7.0 and 7.2, respectively. It was activated by sulphydryl compounds and EDTA while sulphydryl alkylators and blockers were found to inhibit the enzyme activity. Met-2-NNap was found to be the best substrate followed by Thr-2-NNap, His-2-NNap, Leu-2-NNap, Arg-2-NNap and Ala-2-NNap, respectively. The Km values for hydrolysis of various substrates viz., Met-2-NNap, Leu-2-NNap, Arg-2-NNap, Arg-NNapOMe, Thr-2-NNap, His-2-NNap, BANA, Arg-pNA and Lys-pNA were 0.128, 0.167, 0.169, 0.288, 0.428, 0.500, 0.667, 0.195 and 0.476 mM, respectively. The temperature optima for hydrolysis of BANA and Leu-2-NNap were approximately 45 degrees C and approximately 50 degrees C with activation energies of approximately 13.7 and approximately 11.0 kcal mole-1, respectively. The enzyme was fairly stable upto 50 degrees C and between pH 4.0-7.5.