A retrospective hospital-based study on congenital hypothyroidism in the Sultanate of Oman.

A retrospective study was conducted on 45 children with congenital hypothyroidism (CH) to estimate the number of missed cases of CH among Omani children per year and compare the intellectual outcome of children diagnosed by neonatal screening (Group A) with those who were diagnosed clinically at a later age (Group B). Our results revealed 14 children in Group A, diagnosed at a mean age of 2.3 +/- 0.8 months and 31 children in Group B diagnosed at a mean age of 9.8 +/- 2.5 months. IQ assessment revealed that 67 per cent of the children in Group A had a normal IQ compared to only 15 per cent of those in Group B. The above results point to a great demand for a national screening programme in the Sultanate of Oman.

Spontaneous improvement of severe neonatal hyperparathyroidism after failed total parathyroidectomy.

We report an interesting case of severe neonatal hyperparathyroidism (SNHP) treated by sub-total parathyroidectomy, as her fourth parathyroid gland could not be identified. The clinical course changed over time to a more benign course resembling familial hypocalciuric hypercalcemia. This indicates that the natural course of SNHP is probably gradual spontaneous improvement, if patient survives the first few months of life.

Effect of short term immobilization on mechanical characteristics of skeletal muscle in uromastix.

Gastrocnemius muscles of Uromastix were used to observe the effects of short term (7 days) immobilization in flexed position. Results demonstrated significantly (P < 0.01) lesser magnitude as well as rate of rise in isometric twitch and tetanic tensions with insignificantly different twitch/tetanus ratio in the immobilized muscles. Both the twitch and tetanus also demonstrated significantly (P<0.01) higher twitch half relaxation and twitch/tetanus half relaxation time ratio. While, immobilized muscles showed insignificantly higher twitch contraction, tetanus half relaxation and duration of active state as well as peak twitch duration, than control ones. These changes in the mechanical contraction parameters were not found to be associated with changes in weight, resting, stretched and shortened length of the immobilized muscles. A comparison of present results with previous work performed on skeletal muscles of Uromastix at longer period (20 days) of immobilization has suggested that Uromastix muscles are no prone to a significant immobilization atrophy. However, decreased mechanical response after immobilization irrespective of the period of immobilization in Uromastix muscles is probably due to a depletion in various substrates involved in muscle mechanics.

Mechanical response of lizard skeletal muscles to disuse: I. Effect of short-term tenotomization.

The gastrocnemius muscles of the reptile, Uromastix hardwickii were tenotomized for seven days according to the method described earlier and their mechanical responses were recorded to study the effect of cessation of proprioceptive impulses on the functioning of these muscles. The parameters measured were isometric twitch and tetanic tensions, time dependent tension parameters and other time dependent parameters of twitch and tetanus records. The isometric twitch and tetanic tensions, their ratios and the rate of rise in twitch and tetanus along with P/ms were found significantly lesser in the tenotomized muscles. The other time dependent tension parameters, i.e. twitch contraction and tetanus half relaxation times and their ratios were however, unaffected as compared to their controls. The duration of active state on the contrary, was significantly reduced in the tenotomized muscles. The tenotomization effects observed on the mechanical parameters are discussed in terms of muscle fiber architecture and the degree/rate of cross bridge interaction in these muscles.

Mechanical response of lizard skeletal muscles to disuse: II. Effect of short-term denervation.

The gastrocnemius muscles of Uromastix hardwickii were used to determine the effects of the absence of neural influence on them. For this purpose, the muscles were denervated for 7 days and were used to record isometric twitch and tetanus. The contraction parameters thus obtained from the denervated muscles were then compared with their own controls. The isometric tensions and time dependent tension parameters were significantly lower in the denervated muscles. The time dependent parameters, peak duration in twitch and duration of active state in twitch were however, found to be unaffected by short-term denervation with the exception of twitch/tetanus half relaxation time ratio, which was significantly higher in the denervated muscles. The denervation effects observed on the mechanical contraction behaviour of the gastrocnemius muscle have been discussed in terms of electrical excitation, excitation-contraction coupling and cross bridge interaction.

Seasonal variations in the contractile behaviour of gastrocnemius muscles of Uromastix hardwickii.

Seasonal variations in the isometric activity of the isolated gastrocnemius muscle of Uromastix hardwickii was studied from winter to summer in Karachi, Pakistan. A constant 20 degrees C temperature was maintained during experimentation to avoid influence of this factor on seasonal changes. The twitch and tetanic tensions recorded at resting lengths showed a significant rise from winter to summer (p less than 0.0005) with a greater effect on tetanic tensions. The rate of rise of tensions also showed a significant elevation (p less than 0.0005) from winter to summer, while the duration of active state decreased by 66% during spring and summer. The results are discussed in terms of speed of summation of active state, cross bridge interaction, and characteristic expression of gastrocnemius muscle morphology on its mechanical behaviour from winter to summer.

Effect of triturated dilutions of ethanol on the peristaltic contractions of isolated rabbit intestine.

Effect of triturated dilutions of ethanol from to 10(-3) to 10(-24) were studied on the peristaltic contractions of isolated rabbit intestinal pieces. Triturated dilutions of ethanol were applied in two doses. It was generally observed that the addition of first dose was followed by a small increase of 1.1 gms. in the resting tension which occurred at a slower rate in about 36.5 sec. The second doses however, increased the resting tension by 24 gms, in about 21 sec. In addition, the active tensions showed large variations on the application of first doses of triturated ethanol, while the second doses always decreased this parameter below the first dose levels. The rate of contractions was however, unaltered by both the first and second doses of ethanol, although an increase in the contraction times was found to be balanced by a simultaneous decrease either in the peak duration or relaxation times. The results are discussed in terms of electrophysiological, active state and free ionic Ca++ release phenomena.

Effect of temperature on the maximum rate of rise of tension in denervated rat diaphragm muscle.

Effects of chronic denervation and temperature were studied on the maximum rate of rise of tension in isometric twitch and tetanus of rat diaphragm muscles. The muscles were denervated for 15-20 days and the maximum rate of rise of tension was measured according to Hill (1951). The results showed that the maximum rate of rise of tension in twitch and tetanus was temperature dependent, exponentially increasing with increasing temperatures in both the normal and denervated muscles. A further observation was that the maximum rate of rise of tension in denervated muscle was always smaller than normal controls. It is suggested that probable changes in the series elasticity and duration of active state in the denervated muscle are responsible for the observed changes.

A comparative study of the effects of ethanol, acetylcholine and adrenaline on various parameters of intestinal contractions of rabbit.

A comparative study was carried out to observe the effects of ethanol, acetylcholine and adrenaline on various parameters of the contraction cycle of rabbit intestine. Acetylcholine and adrenaline were used in concentrations of 10(-3), either alone or in combination with absolute ethanol. The results showed that ethanol and acetylcholine had no effect on the rate of intestinal contractions while adrenaline increased it significantly. However, all these drugs decreased the active tension of the contracting intestine, the decrease being minimum for ethanol, moderate for acetylcholine and maximum for adrenaline. On the contrary, a small transient decrease in resting tension was produced by ethanol and this occurred at a very fast rate while adrenaline produced a marked decrease in this parameter, its rate being 6-10 times slower. Ethanol and acetylcholine were also found to increase the resting tension, it being 2 times greater and occurring at a faster rate with acetylcholine. It is suggested that these drugs produce their effect by altering resting membrane potential, Ca++ and other ion fluxes.

Effect of Mukteswar and Komarov strains of newcastle disease vaccines on egg production.

Effect of live mesogenic strains of Mukteswar and Komarov ND vaccines was studied on the egg production of laying birds. The results showed that pullets vaccinated with Mukteswar ND vaccine produced more eggs than the Komarov vaccinated or non vaccinated birds. The peak egg production was noted at the age of 29 weeks in these birds and this latter decreased. When birds were re-vaccinated with the same vaccine and route, at the age of 32 weeks, the egg production again increased to 81%. Intra muscular vaccination with Komarov ND vaccine demonstrated 11% less egg production than the birds vaccinated with Mukteswar ND vaccine. In all the experiments, birds were found to be severely affected by the hot weather resulting in a drop of egg production.

Effect of hypothermia on the twitch and tetanic contractions of denervated rat diaphragm muscle under isotonic conditions.

Effect of hypothermia was studied on the twitch and tetanic contractions of the chronically denervated rat diaphragm muscles under isotonic conditions. The muscles were denervated for 15-20 days and the temperature was lowered from 35 degrees C to 15 degrees C. The results showed that hypothermia and chronic denervation had very little effect on the isotonic contraction parameters since these were found to be unaltered at all temperatures except at 15 degrees C. It is suggested that denervation has no significant effect on the contractile component of our experimental muscles.

The effect of caffeine on normal and denervated gastrocnemius muscles of Uromastix hardwickii.

The effect of time and 5 mM caffeine was studied on the maximum twitch tension of the normal and 11-13 days denervated gastrocnemius muscles of Uromastix hardwickii. The maximum twitch tension was found to decrease with time and it remained about 68% of initial after 60 minutes at 20 degrees C. Five mM caffeine only produced potentiation in normal and denervated muscles while there was no contracture in either muscle. Although caffeine increased the overall contraction and relaxation times in control muscles, it was more effective on the contraction time of the denervated muscles in which the contraction time increased with time. Denervated muscles were seen to be less sensitive to caffeine as the contraction times increased with time (at about 30-40 minutes) in these muscles while in normal control muscles the contraction time increased immediately. The action of caffeine in relation to these effects is discussed.