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Biomedical subjects

F Khan

Publications and source records attributed to F Khan.

At least 163 records · Page 9Linked to original sources
PubMed1989

Deficient neurogenic innervation of the myenteric plexus with normal submucous plexus involving the entire small and large bowel.

A newborn presented with a picture of intestinal obstruction. Multiple biopsies of the small and large bowel showed an unusual neurogenic innervation. The myenteric plexus of Auerbach was severely depleted of ganglion cells and nerve fibers, while the submucous plexus of Meissner was normally innervated. An ileostomy failed to function and extended trial with experimental smooth muscle stimulant (Cisapride) was equally ineffective. The patient was finally treated by a myectomy from the duodenum to the descending colon with a sigmoid colostomy. This procedure, coupled with a Nissen fundoplication, stopped the vomiting and allowed normal defecation through the colostomy. The patient is presently taking increasing increments of oral fluids with a concomitant decrease in the volume of parenteral nutrition. The myectomy initiated marked hypertrophy of the muscularis mucosa. Could this muscular hypertrophy account for the improvement in bowel function? Possible etiology will be discussed. We caution that rectal submucosal suction biopsy alone may be misleading if normal ganglion cells and nerve fibers are found, yet the patient's clinical symptoms fail to improve. A full thickness bowel wall biopsy is then recommended.

Ganglia, Parasympathetic↗
PubMed1988

Differential oscillator strengths and dipole polarizabilities for transitions of the helium sequence.

The dipole radial integral for an initial discrete 1s state and a final continuum state has been calculated under the screened hydrogenic model. In this model, single-electron hydrogenic wave functions are employed and the initial and the final states are treated by two different effective-charge parameters. Numerical values of differential oscillator strengths for transitions from 1s 21S to the continuum for the helium sequence ions are obtained. Also calculated are the dipole polarizabilities, which are found to be in excellent agreement with the results of other authors.

Electrons↗
PubMed1988

1s2 1S-1s np 1P transitions of the helium isoelectronic sequence members up to Z = 30.

Radial integrals have been calculated under the one-electron hydrogenic model. Two different values of the effective charge parameter, one for the initial state and the other for the final state, are retained in these formulae. The model is able to reasonably reproduce the existing dipole oscillator strength values with little effort. The dipole oscillator strength values are given for many ions for the first time.

Electrons↗
PubMed1988

Computer-derived equations for predicting survival postoperatively. Their usefulness and limitations.

We used multivariate analysis to determine whether survival following perforations of the gastrointestinal tract could be accurately predicted from preoperative data. Of 12 variables tested, four were found to have predictive value. These were age, pulmonary disease, preoperative shock, and the attending surgeon. When these four variables were employed in a logistic regression equation on 42 patients, it correctly predicted which 21 patients died before leaving the hospital. To produce an equation useful for other hospitals, we recalculated it without the attending surgeon variable. Again, the equation was used to predict survival. The correlation of predicted vs observed outcome remained high, and, using a 2 x 2 chi 2 test, the correlation was significant. We then cross validated the three-variable model on data from a second hospital. The model accurately predicted the new data equally well. We believe that predictive models can identify risk factors in a variety of patient populations and can determine who is likely to benefit from specific treatment modalities.

Age Factors↗
PubMed1988

Static multipole polarisabilities and second-order Stark shift in francium.

The multipole polarisability of the ground state of francium is calculated by utilising both the variational technique of Davison and the quantum defect theory underlying the Bates-Damgaard method. This approach is also shown to yield reasonable results for other alkali atoms. Second-order Stark shift for the ground state of francium is presented as a function of field strength for possible future experimental comparison.

Cesium↗
PubMed1988

The effect of prazosin on skin microcirculation as assessed by laser Doppler flowmetry.

1. Laser Doppler flowmetry was used in six normal volunteers to record changes in fingertip skin blood flow after the administration of prazosin to block postsynaptic alpha 1-adrenoceptors. 2. Prazosin (0.5 mg orally) did not alter systolic or diastolic blood pressure or heart rate. 3. Prazosin did significantly increase basal skin blood flow 2 h after its administration but this effect was no longer evident after contralateral hand warming. Prazosin markedly reduced the skin vasoconstrictor response to deep inspiration and to contralateral hand cooling. 4. This study suggests that postsynaptic alpha 1-adrenoceptors are involved in maintaining skin vasoconstrictor tone at rest and are also involved in the rapid skin vasoconstriction seen in response to a deep inspiration and to contralateral hand cooling.

Adult↗
PubMed1988

Asymptotic screened hydrogenic radial integrals.

The screened hydrogenic radial dipole integral for discrete-discrete transitions from initial state n'l' to final state nl is asymptotically expanded to the lowest order such that the final quantum number n --> infinity. The analytical expression obtained is in terms of confluent hypergeometric functions, and explicit expressions for a few of the specific transitions are derived from them as examples.

Electrons↗
PubMed1988

Pneumonia in the elderly: a review.

Elderly persons are at increased risk of acquiring pneumonia. Morbidity and mortality rates from pneumonia are also higher. Clinical manifestations of pneumonia in the elderly are frequently very subtle; however, a high index of suspicion will induce the physician to obtain a chest roentgenogram. A new lung infiltrate will confirm the diagnosis. Although the Gram's stain of a sputum smear is most helpful in the initial selection of a specific antibiotic, a good quality sputum is not usually available in the elderly, and empiric therapy reduces the morbidity and mortality from pneumonia.

Aged↗
PubMed1987

Pneumomediastinum after cocaine smoking.

We have reported two cases of pneumomediastinum occurring in previously healthy young men after smoking cocaine and performing the Valsalva maneuver to intensify the euphoria. Pneumomediastinum is thought to result from increased intrathoracic pressure produced by the Valsalva maneuver, with resultant rupture of marginal alveoli. With the increasing popularity of inhaling free-base cocaine, physicians should be aware of this complication.

Adolescent↗
PubMed1986

Lymphocyte traffic effects of systemic and local lidocaine in sheep.

The traffic of lymphocytes through lymphoid tissues is of importance in both the initiation and development of the immune response. The effects of lidocaine on lymphocyte traffic through primary peripheral lymph nodes of sheep (popliteal and pre-femoral) was investigated by three routes of lidocaine administration. Infiltration of lidocaine above the study node and as the sole anesthetic agent for study node efferent lymphatic cannulation produced mild depressions in lymphocyte outputs into study node efferent lymph. This depression was comparable to that encountered with regional epidural anesthesia for similar operations, but was significantly less than that associated with general anesthesia (P less than 0.000015). In animals with established chronic cannulation of study node efferent lymphatics, both study node drainage area injection of lidocaine and systemic administration of lidocaine (intravenously by bolus injection at a distant site) produced prompt and sharp depressions in lymphocyte traffic as mirrored in the output of lymphocytes into study node efferent lymph. The output of both small recirculating lymphocytes and of blast lymphocytes was affected.

Anesthesia, General↗
PubMed1986

Treatment of respiratory tract infections with ciprofloxacin.

The efficacy and safety of ciprofloxacin in an oral dose of 750 mg twice daily, in the treatment of respiratory infections was studied in 129 patients. Ciprofloxacin showed broad in-vitro antibacterial activity and was highly effective in both Gram-negative and Gram-positive infections with a clinical cure rate of 96%. The major side effect was an interaction with theophylline particularly in the elderly patients.

Adult↗
PubMed1985

Spinal tuberculosis revisited.

Although the incidence of tuberculosis is decreasing, spinal tuberculosis is still an important disease. Delay in diagnosis and treatment results in long-term disability. We reviewed our cases of spinal tuberculosis diagnosed between 1975 and 1982, with special reference to those features that permit early diagnosis. Among the nine cases diagnosed, roentgenographic evidence of pulmonary tuberculosis (7/9) and positive PPD test (8/8) were found to be highly suggestive diagnostic clues. Computerized tomography (CT) of the spine was a useful way of determining the extent of the disease and following response to therapy. Various modes of therapy were used, and the outcome was related to the extent of the disease and duration of symptoms before initiation of therapy. In early stages, medical therapy alone is adequate; surgical intervention is necessary in cases with neurologic features.

Adult↗