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Biomedical subjects

P J Patel

Publications and source records attributed to P J Patel.

At least 19 recordsLinked to original sources
PubMed1998

Cutis verticis gyrata: its computed tomographic demonstration in acromegaly.

A retrospective review of the 17 cases of acromegaly, recorded in the hospital and with available CT scans was undertaken in order to determine the presence and of cutis verticis gyrata (CVG) frequency, and the spectrum of other associated radiographic appearances of CVG. The hormone levels were analysed, and the histopathology of the surgical specimens reviewed. Five cases were uncovered. In these, the scalp in CVG was markedly thickened with convoluted, gyriform or cog-wheel appearances. There was no correlation in the age, sex, duration of symptoms or the hormone levels in these two groups of acromegalics: with or without CVG. All cases were histologically pituitary adenoma. It is concluded that CVG is not uncommon in acromegaly. Its presence on a CT scan should caution the radiologist to the presence of pituitary adenoma or any of the other neurological causes of CVG.

Acromegaly↗
PubMed1996

Renal sonographic patterns in Bartter's syndrome.

The renal sonographic findings in ten cases of Bartter s syndrome investigated at the King Khalid University Hospital, Riyadh, Saudi Arabia are described. There were various sonographic abnormalities other than those of hyperechoic pyramids as previously described. These were diffuse increased renal echogenicity and hyperechoic echogenicity in the kidneys with the exception of the pyramids. This condition can be suspected early if nephrocalcinosis is present in a child with a history of polyhydramnios and premature delivery.

Bartter Syndrome↗
PubMed1996

Correlation of in vivo topical efficacies with in vitro predictions using acyclovir formulations in the treatment of cutaneous HSV-1 infections in hairless mice: an evaluation of the predictive value of the C* concept.

The purpose of this study was to carry out an extensive examination of the C* concept for prediction of the topical antiviral efficacies of acyclovir (ACV) formulations in a hairless mouse model for the treatment of cutaneous herpes simplex virus type-1 (HSV-1) infections. This method is based on estimation of the free drug concentration at the target site (C*), which is presumed to be the basal cell layer of the epidermis. Five different formulations (containing 5% ACV) were examined in a finite dose multiple dosing regimen (twice a day application) to simulate the clinical situation. For determination of C*, in vitro ACV fluxes across the hairless mouse skin were measured in an in vivo-in vitro experimental design that approximated the in vivo antiviral treatment protocol. Then, the in vivo antiviral efficacies were measured using a 1-day delayed (after HSV-1 virus inoculation) 4-day treatment protocol. 10 microL/cm2 dose of ACV formulation was applied every 12 h for 4 days after which the lesions were scored and efficacies were calculated. Our results indicate that, over a wide range of efficacies, the predictions based on C* (estimated from the experimental fluxes) are in good agreement with the in vivo antiviral efficacies. These studies, therefore, support the validity of the C* concept for various ACV formulations and suggest that the C* approach has potential for future practical situations.

Acyclovir↗
PubMed1995

Multiple congenital malformations in two sibs reminiscent of hydrolethalus and pseudotrisomy 13 syndromes.

We report on two sibs, born to consanguineous parents, with defects of the midline including cleft lip and palate, flat nose, hypotelorism, and dysgenesis of corpus callosum, in addition to short limbs, radiolucent tibial notch, digital anomalies, ambiguous genitalia, and hypopituitarism. In spite of the similarities between this condition and the hydrolethalus and pseudotrisomy 13 syndromes, our patients had neither preaxial nor postaxial polydactyly, but had previously undescribed bilateral radiolucent tibial notch, which is not known to be part of those two syndromes. The cases presented here may very well represent a new autosomal recessive syndrome.

Abnormalities, Multiple↗
PubMed1995

Adrenoleukodystrophy: CT and MRI findings.

A case of adrenoleukodystrophy (ALD) with CT and MRI findings is described. The CT scan showed low densities in the white matter of the parietal and occipital lobes. No calcifications were seen. Post-contrast CT showed an abnormal enhancement within the involved white matter. MRI showed changes of demyelination around the atria of the lateral ventricles bilaterally involving the posterior aspect of the cerebrum symmetrically. The posterior part of the posterior corpus callosum, splenium and pyramidal tracts also showed increased signal intensity. From a review of the literature, these findings are typical of the radiological changes seen in ALD. ALD can be diagnosed from typical history and biochemical changes as well as from CT and MRI findings.

Adrenoleukodystrophy↗
PubMed1995

Ambiguous genitalia: comparative role of pelvic ultrasonography and genitography.

Ambiguous genitalia represents a true medical and social emergency which needs a multi-disciplinary team approach for elucidation. The paediatric radiologist plays an important role in defining the genital anatomy which remains one of the most important factors in sex determination. Aiming to compare the predictive value of pelvic ultrasonography and genitography in sex determination in patients with ambiguous genitalia, we retrospectively reviewed the medical records of 69 patients, 53 females and 16 males, where both procedures were employed. In female pseudohermaphroditism, the presence of a uterus with or without vagina was predicted in 46 (86.8%) patients by ultrasound compared with 44 (83%) patients in whom a genitogram revealed a vagina +/- uterus. In six (11.3%) patients, a genitogram revealed a male-type urethra. The combination of ultrasound and genitogram, however, was more sensitive and predicted the presence of a uterus with or without vagina in 52 (98.1%) patients. In male pseudo-hermaphroditism, there was no false positive by ultrasound, and a genitogram revealed a male-type urethra in 12 (75%) patients. In conclusion, although real time pelvic ultrasonography is less invasive than genitography, its yield in elucidating genital anatomy is comparable. The combination of both procedures is more informative and has a better yield.

Child↗
PubMed1994

Symmetrical lesions in the basal ganglia.

Bilateral and symmetrical non-space occupying lesions in the basal ganglia of 27 cases were studied. Nine cases had low attenuation lesions while the remaining 18 had high attenuation lesions due to bleeding or calcifications. The clinical presentations and final diagnosis were collated and related to these changes. In the low-attentuation cases, definite hypoxic-ischaemic insults were the aetiological basis for low attenuation lesions in 3 cases; and hypothesised to be the basis in the remaining six. Amongst the high attenuation group, bleeding was noted in 4 cases with trauma or cardiac arrest. The remainder had calcifications. It is suggested that a hypoxic-ischaemic pathophysiological phenomenon might have also accounted for some of these calcifications. The co-existence of both low and high attenuation lesions in the same patients in some of our cases tends to lend credence to this hypothesis.

Adult↗
PubMed1993

Inhibition and inactivation of presynaptic cholinergic markers using redox-reactive choline analogs.

Inhibition and inactivation of two presynaptic cholinergic "markers", choline acetyltransferase and high affinity choline transporter, has been investigated using inhibitors designed with a redox-reactive catechol tethered to a quaternary ammonium group. Two quaternary ammonium alkyl-substituted catechols, 3[(trimethylammonio)methyl]catechol (TMC, 1) and N,N-dimethylepinephrine (catecholine, 2) were shown to bind weakly and noncompetitively to bovine choline acetyltransferase yet inactivated the enzyme in a time course consistent with the involvement of early intermediates in the spontaneous oxidation of these catechols. Both agents also inhibited high-affinity choline uptake. The time course of TMC and catecholine spontaneous oxidation-dependent inactivation of high affinity choline uptake sites was slower than, if it occurred at all, the spontaneous degradation of measurable choline transport in synaptosomes. When compared with inhibition of uptake of other neurotransmitters, it was shown that catecholine demonstrated more selectivity than TMC toward inhibition of choline transport. Km (microM) and Vmax (pmol/min per mg of protein) were measured for high affinity transport of choline, dopamine, and serotonin and were observed to be Km = 2.04 +/- 0.31, Vmax = 22 +/- 1; Km = 1.4, Vmax = 53; and Km = 0.15, Vmax = 23, respectively, in good agreement with published literature values. Ki's (mM) for catecholine and TMC, calculated from experimentally determined IC50's, were for catecholine 0.13 +/- 0.06, 0.53 +/- 0.09, and 0.39 +/- 0.10, and for TMC 0.06 +/- 0.03, 0.09 +/- 0.03, and 0.09 +/- 0.08, for choline, dopamine, and serotonin transport, respectively. In vivo studies using catecholine suggest that this compound impairs learning ability associated with long-term memory. Thus, catecholine represents a lead compound in a potential series of redox-reactive choline analogs, which may become useful irreversible antagonists of the critical cholinergic macromolecular targets underlying cholinergic hypofunction in disorders such as Alzheimer's disease.

Animals↗
PubMed1992

Osteopetrosis: brain ultrasound and computed tomography findings.

A case of osteopetrosis presenting with rare features of dysmorphism with proptosis due to hypoplasia of the orbits and the temporal bone is described. The case also had calcifications in the periventricular regions, the falx cerebri and the corpora colliculi. These features and sonographic findings of osteopetrosis have not been reported previously. The sensitivity and specificity of imaging modalities in the diagnosis of intracranial calcifications is discussed.

Brain↗
PubMed1992

CT findings in paranasal aspergillosis.

Computed tomographic (CT) scan of eight cases of paranasal sinus aspergillosis were reviewed. Different CT patterns were observed such as areas of high densities, linear interlacing network of high density, radiolucent thin rim periphery to the masses, calcification, expansion of involved sinuses and bone erosion. Two cases of invasive type showed extension beyond the sinuses into the orbit and intracranially simulating a malignant tumour. The findings are similar to those described by previous authors. The differential diagnosis is also discussed.

Adult↗
PubMed1992

Imaging of infantile polycystic kidney disease with some rare association.

Seventeen patients, age 1 day to 6 years with infantile polycystic kidney disease were evaluated with ultrasound and other imaging techniques. Most patients showed bilaterally enlarged kidneys with hyperechoic renal parenchyma, which had poor differentiation in outlines as well as between renal sinus, cortex and medulla. Cysts of various sizes were also identified in the kidneys. However, a third of these cases showed well-defined renal outlines, normal echogenic cortical rim, whilst dilated renal collecting systems were seen in another third of the cases. Twelve cases showed hepatomegaly. Few rare findings such as liver cysts, associated Meckel syndrome, renal stone, bilateral vesicoureteric reflux and renal calcification were also noted. This study confirms the diagnostic value of sonography and intravenous pyelography examination. However, the noninvasiveness and the opportunity for repeat examination in antenatal and postnatal life makes sonography the ideal investigative modality.

Child, Preschool↗
PubMed1991

Redox reactive reagents inhibiting and inactivating choline acetyltransferase.

3-Trimethylammoniomethyl catechol and N,N-dimethylepinephrine (catecholine) are redox reactive reagents which possess quaternary ammonium functional groups and the capacity to inhibit or inactivate choline binding macromolecules which mediate cholinergic neuronal function. Earlier studies reported the synthesis of 3-trimethylammoniomethyl catechol and demonstrated its redox-dependent covalent inactivation of the nicotinic acetylcholine receptor (Nickoloff et al., Biochemistry 24, 999-1007 (1985)]. Here we present the synthesis of catecholine and show that both 3-trimethylammoniomethyl catechol and catecholine are weak noncompetitive inhibitors (Ki = 15 +/- 6 and 25 +/- 4 mM, respectively) of choline acetyltransferase (EC 2.3.1.6). Both agents irreversibly inactivate the enzyme.

Animals↗
PubMed1991

Ambiguous genitalia: medical, socio-cultural and religious factors affecting management in Saudi Arabia.

Twenty-eight children with ambiguous genitalia were seen at King Khalid University Hospital over a 6-year period. The incidence of this disorder was 0.4/1000 live births. Of the total, 21 (75%) were Saudis and seven (25%) were non-Saudis. The consanguinity rate was 67.9%. Twenty-four (85.7%) were born in hospital and four (14.3%) at home. In only three (10.7%) was the news first broken to the parents by a senior doctor, in 13 (46.4%) by a junior doctor, and in 11 (39.3%) by a nurse. Ambiguous genitalia were observed in 22 (78.6%) at birth and in six (21.4%) were picked up later. Owing to a lack of immediate investigative facilities and for some socio-cultural reasons, 19 of the latter groups were assigned sex without prior investigations. There was an obvious preference to assign male sex. On investigation, 13 (46.4%) had XX chromosomes, 11 (39%) XY and one (3.6%) XO: in three (10.7%), chromosomal results were not available. There were 14 cases (50%) of congenital adrenal hyperplasia, two of 5-alpha reductase deficiency (7.1%), and five of testicular feminization syndrome (17.9%), in addition to others. After investigation, five (17.9%) of the children needed sex reassignment. This was accepted by two and rejected for socio-cultural reasons by three. The opinion of the religious leaders was obtained. Some recommendations on management of these cases are made, based on our local experience.

Disorders of Sex Development↗
PubMed1991

Gaseous distension of the gut during intravenous urography.

During intravenous urography, the changes in the gastrointestinal tract were assessed in a total of 101 patients within two subgroups: allergic and non-allergic, depending on the patient's reaction or non-reaction to the intravenously injected Conrary 420. The gastrointestinal changes were either nil (that is normal) or abnormal with definite increase in the total volume of gas in the abdomen. Increased gas was commoner (66%) among the non-allergic group as compared with 34% of the allergic group. The aetiological basis being postulated for this observation includes biochemical and chemical changes as well as allergic response within the gut.

Contrast Media↗
PubMed1991

Cerebrovascular disease in Saudi Arabia.

We studied the pattern and outcome of strokes in 200 Saudi patients. Cerebral infarction constituted 87% of strokes, subarachnoid hemorrhage 4.5%, cerebral hemorrhage 6.5%, and venous infarction 2%. The vessel most commonly involved was part or all of the middle cerebral artery, constituting 52% (90) of the 174 arterial infarcts. Lacunar infarcts were seen in 21% (37) of the patients with arterial infarcts. Among all 200 patients, 8% died and 8% had secondary generalized seizures. Hypertension occurred in 41% of the 174 patients with arterial infarcts and 62% of the 13 with cerebral hemorrhages. The highest incidence of hypertension as a risk factor was among those with lacunar infarcts (81%), ganglionic cerebral hemorrhages (80%), and infarcts of deep branches of the middle cerebral artery (57%). Embolic infarcts due to rheumatic heart disease constituted 11% of all arterial infarcts. We conclude that our pattern of strokes is similar to that of the west rather than that of the Japanese, but with less frequent arteriovenous malformations and aneurysms.

Adult↗