Crude cellulase from oil palm empty fruit bunch by Trichoderma asperellum UPM1 and Aspergillus fumigatus UPM2 for fermentable sugars production

Cellulase is an enzyme that converts the polymer structure of polysaccharides into fermentable sugars. The high market demand for this enzyme together with the variety of applications in the industry has brought the research on cellulase into focus. In this study, crude cellulase was produced from oil palm empty fruit bunch (OPEFB) pretreated with 2% NaOH with autoclave, which was composed of 59.7% cellulose, 21.6% hemicellulose, and 12.3% lignin using Trichoderma asperellum UPM1 and Aspergillus fumigatus UPM2. Approximately 0.8 U/ml of FPase, 24.7 U/ml of CMCase and 5.0 U/ml of β-glucosidase were produced by T. asperellum UPM1 at a temperature of 35 °C and at an initial pH of 7.0. A 1.7 U/ml of FPase, 24.2 U/ml of CMCase, and 1.1 U/ml of β-glucosidase were produced by A. fumigatus UPM2 at a temperature of 45 °C and at initial pH of 6.0. The crude cellulase was best produced at 1% of substrate concentration for both T. asperellum UPM1 and A. fumigatus UPM2. The hydrolysis percentage of pretreated OPEFB using 5% of crude cellulase concentration from T. asperellum UPM1 and A. fumigatus UPM2 were 3.33% and 19.11%, with the reducing sugars concentration of 1.47 and 8.63 g/l, respectively.

Age at menarche among school girls in Sokoto, Northern Nigeria

BACKGROUND/OBJECTIVES

Menarche, the first menstrual period, is influenced by many factors including socio-economic status and rural or urban dwelling. The aims of the study were to compare the age at menarche between rural and urban girls and evaluate the anthropometric indices at menarche.

MATERIALS AND METHODS

A cross-sectional study of rural secondary school girls and urban school girls. A structured questionnaire was used to obtain information on their age at menarche and other relevant data. Their weights and heights were measured using computerized scales and calibrated walls.

RESULTS

Two hundred and twenty eight (228) rural girls and four hundred and eighty (480) urban girls that had attained menarche within a year were studied. Mean age at menarche for all the girls was 15.26 years. Mean menarcheal age for the rural and urban girls were 15.32 years and 15.20 years, respectively. Mean weight and height were 47.6 kg and 156.76 cm, respectively for the rural girls and 48.12 kg and 156.8 cm, respectively for the urban girls. There was no significance difference in age of menarche among the groups (P > 0.05).

CONCLUSION

The mean age at menarche for the school girls is 15.26 years. There was no difference in menarcheal age between the rural and urban school girls. Further longitudinal studies to compare rural school girls and urban school girls in private schools are required.

Adsorption of crude oil from aqueous solution by hydrogel of chitosan based polyacrylamide prepared by radiation induced graft polymerization

The adsorption of crude oil (initial concentration 0.5-30 g/L) from aqueous solution using hydrogel of chitosan based polyacrylamide (PAM) prepared by radiation induced graft polymerization has been investigated. The prepared hydrogel was characterized by FTIR and SEM micrographs. The experiments were carried out as a function of different initial concentrations of oil residue, acrylamide concentration, contact time and pH to determine the optimum condition for the adsorption of residue oil from aqueous solution and sea water. The results obtained showed that the hydrogel prepared at concentration of 40% acrylamide (AAm) and at a radiation dose of 5 kGy has high removal efficiency of crude oil 2.3g/g at pH 3. Equilibrium studies have been carried out to determine the capacity of the hydrogel for adsorption of crude oil, Langmuir and Freundlich adsorption models were applied to describe the experimental isotherms and isotherms constants. Equilibrium data were found to fit very well with both Freundlich and Langmuir models. Also the adsorption of oil onto the hydrogel behaves as a pseudo-second-order kinetic models rather than the pseudo-first-order kinetic model.

Laparoscopic Trachelectomy for Cervical Stump 'Carcinoma in situ'

A 43-year-old, who underwent a subtotal hysterectomy for postpartum hemorrhage following a normal delivery, 10 years ago, presented with a history of persistent vaginal discharge and post-coital bleeding. A pap smear reported moderate dysplasia, and a subsequent colposcopic biopsy reported severe dysplasia with crypt extension. The patient underwent a laparoscopic trachelectomy, and histology of the stump reported cervical squamous carcinoma in situ, with no microinvasion.

Vesicovaginal fistula: do the patients know the cause?

BACKGROUND

So much has been written on vesicovaginal fistula (VVF) but there is little on the patients' perspective of the condition. The objectives of this study were to determine the knowledge of patients who have developed VVF on the causes of the fistula and their attitude toward measures that would prevent future occurrence.

METHODS

The questionnaire-based survey was conducted on VVF patients on admission from June to August 2003 at Maryam Abacha Women and Children Welfare Hospital, Sokoto, Nigeria. The case notes of the patients were reviewed after the interview to match the responses from the patients with those documented in the folders. Focus group discussions were held with the maternity staff to ascertain the content and quality of existing counseling.

RESULTS

One hundred and thirty patients were studied out of which 121 (93%) had no formal education. Teenagers constituted 37%, while 57% were primiparae. Thirty-five (27%) patients were divorced or separated because of the VVF. There were seven cases of recurrence after a previous successful repair. Prolonged obstructed labor was the cause of the VVF in 110 (85%) patients and 77 (70%) correctly attributed their problem to the prolonged labor. The 33 patients who could not identify the prolonged obstructed labor as the cause either attributed their condition to God/destiny or to the operation that was done to relief the obstruction and therefore would not have hospital delivery in their subsequent pregnancies. From the focus group discussions, it was confirmed that pre and post-operative counseling were inadequate.

CONCLUSION

Even though majority (70%) of the patients knew the cause of their fistula from the health talks, some (32%) would still not change from risky obstetric behavior. Mandatory provision of accurate and appropriate information and education to all VVF patients and their relatives or spouses by trained counselors should be ensured. Such information and education should emphasize the etiology and management of obstetric fistula in order to prevent a recurrence.

Nitrification of ammonium-rich sanitary landfill leachate

The nitrification of ammonium-rich wastewater is considered challenging due to the substrate inhibition particularly in the form of free ammonia (FA) and free nitrous acid (FNA) in ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB). The feasibility of the nitrifying activated sludge system to completely nitrify synthetic stabilized landfill leachate with N-NH(4)(+) concentration of 1452mg/L was tested in this study. The process started with 0.4kg N-NH(4)(+)/m(3)/day of nitrogen loading rate (NLR) in a fed-batch mode to avoid any accumulation of the FA and FNA in the system followed by increasing the nitrogen loading rate (NLR) gradually. Complete nitrification was achieved with a very high ammonium removal percentage (approximately 100%). The maximum specific and volumetric nitrification rate obtained were 0.49g N-NH(4)(+)/g VSS/day and 3.0kg N-NH(4)(+)/m(3)/day, respectively which were higher than those reported previously for ammonium-rich removal using activated sludge system. The nitrifying sludge exhibited good settling characteristics of up to 36mL/g VSS and a long SRT of more than 53 days which contributed to the success of the nitrification process. The coexistence and syntrophic association of the AOB and NOB was observed by using Fluorescence in situ hybridization (FISH) technique which supported the results on complete nitrification obtained in the system. These findings would be of prominent importance for further treatment of actual sanitary landfill leachate.

Measuring organic carbon, nutrients and heavy metals in rivers receiving leachate from controlled and uncontrolled municipal solid waste (MSW) landfills

Since landfilling is the common method of waste disposal in Malaysia, river water is greatly exposed to the risk of contamination from leachate unless proper leachate management is carried out. In this study, leachates from three different types of landfills, namely active uncontrolled, active controlled and closed controlled, were characterized, and their relationships with river water chemistry were examined monthly for a year. The influence of leachate on river water chemistry from each type of landfill depended on many factors, including the presence of a leachate control mechanism, leachate characteristics, precipitation, surface runoff and the applied treatment. The impact of leachate from an active uncontrolled landfill was the highest, as the organic content, NH(4)(+)-N, Cd and Mn levels appeared high in the river. At the same time, influences of leachate were also observed from both types of controlled landfills in the form of inorganic nitrogen (NH(4)(+)-N, NO(3)(-)-N and NO(2)(-)-N) and heavy metals (Fe, Cr, Ni and Mn). Improper treatment practice led to high levels of some contaminants in the stream near the closed controlled landfill. Meanwhile, the active controlled landfill, which was located near the coastline, was exposed to the risk of contamination resulting from the pyrite oxidation of the surrounding area.

Are the demographics for squamous cell cancer in the head and neck changing in the United Kingdom?

Head and neck squamous cell carcinoma is well known to be more common in men than women. Smoking and alcohol are the key risk factors causing such malignancies and there are several publications which have suggested that the prevalence of these diseases is increasing more in women than in men in western countries due to increased smoking and alcohol use. We collected our data at the Institute of Laryngology and Otology from the last 45 years and analysed the disease ratios in male to female patients in different sites within the head and neck. Our results revealed a decreasing male to female ratio, though this was not statistically significant. However, it draws attention to the increasing number of women with head and neck cancer, which may reflect their increasing use of cigarettes and alcohol.

Enzyme Production and Profile by Aspergillus niger During Solid Substrate Fermentation Using Palm Kernel Cake as Substrate

The oil palm sector is one of the major plantation industries in Malaysia. Palm kernel cake is a byproduct of extracted palm kernel oil. Mostly palm kernel cake is wasted or is mixed with other nutrients and used as animal feed, especially for ruminant animals. Recently, palm kernel cake has been identified as an important ingredient for the formulation of animal feed, and it is also exported especially to Europe, South Korea, and Japan. It can barely be consumed by nonruminant (monogastric) animals owing to the high percentages of hemicellulose and cellulose contents. Palm kernel cake must undergo suitable pretreatment in order to decrease the percentage of hemicellulose and cellulose. One of the methods employed in this study is fermentation with microorganisms, particularly fungi, to partially degrade the hemicellulose and cellulose content. This work focused on the production of enzymes by Aspergillus niger and profiling using palm kernel cake as carbon source.

Effect of new poly 2-acryloyl-N,N'-bis (4-nitrophenyl) propandiamide and poly 2-acryloyl-N,N'-bis (4-methylphenyl) propandiamide and their synergistic action on the stability of nitrocellulose

The stability of nitrocellulose can be significantly improved by incorporating two novel polymeric compounds as new stabilizers, each has two p-substituted phenyl rings in its repeating unit. The two prepared polymers were used independently and in three different blend ratios in comparison with the conventional propellant stabilizer, diphenylamine. The efficiency of the prepared stabilizers and their synergistic effect were evaluated using thermo gravimetric analysis (TGA), Bergmann-Junk test and differential scanning calorimetry (DSC). It was found that both polymers and their 50%:50% blend ratio are more efficient nitrocellulose stabilizers than diphenylamine.

Differential scanning calorimetry to investigate the compatibility of ciprofloxacin hydrochloride with excipients

The compatibility between ciprofloxacin hydrochloride (CFX) and some excipients was evaluated using differential scanning calorimetry (DSC). Physical mixture, coground mixture, compressed mixture and kneaded mixture were prepared to study the effect of sample manipulation. In addition, the samples of physical mixture were also accelerated at 55 degrees C for three weeks to obtain more reliable conclusions. Different types of excipients currently used in tablet or capsule formulations namely, calcium phosphate dibasic dihydrate (Emcompress), magnesium stearate lactose, sorbitol, mannitol, croscarmellose sodium (Ac-Di-Sol), sodium carboxymethyl starch (Primojel), microcrystalline cellulose (Avicel PH 101, Emcocil) were examined. The DSC scan of CFX displayed two endothermic peaks probably as a result of a fusion process followed by a decomposition process. CFX appeared to interact with sorbitol, mannitol, Ac-Di-Sol, Primojel, Avicel PH 101 and Emcocil.

A prospective randomized comparison of sequential versus monoculture systems for in-vitro human blastocyst development

BACKGROUND

Extending the period of in-vitro culture to the blastocyst stage may improve implantation rates in IVF treatment. Recognition of the dynamic nature of early embryo metabolism has led to the development of commercially available sequential culture systems. However, their improved efficacy over monoculture systems remains to be demonstrated in prospective studies.

METHODS

Embryos obtained from 158 women undergoing IVF treatment were randomized by sealed envelopes to culture in one of three systems: (A) culture for 5 days in our own monoculture medium (Rotterdam medium); (B) culture for 3 days in Rotterdam medium followed by 2 days in fresh Rotterdam medium; (C) culture for 5 days using the commercially available G1/G2 sequential culture system.

RESULTS

There were no significant differences in blastulation, implantation or pregnancy rates between the three tested culture systems.

CONCLUSION

The employed monoculture system is as effective as the G1/G2 sequential system for the culture of blastocysts for IVF.

Health profile of lock factory workers in Aligarh

In order to assess the health problems and its relationship to the nature of work of lock factory workers, a field based cross sectional study was carried out in sixty randomly selected lock factories in urban industrial areas of Aligarh city. Nine hundred fifty seven lock factory workers were included in the study out of them 45.7 percent were found to be suffering from one or more than one diseases. Detailed study of the workers showed that 73.05 percent were suffering from respiratory tract diseases, a majority of them having upper respiratory tract infection. Diseases showed a definite trend either increasing (Chronic bronchitis, Emphysema etc) or decreasing (upper respiratory tract infection, Bronchial asthma, Injuries & accidents), according to the age and duration of work. Polishing & filing appeared to be the most hazardous type of the work as shown in the proportion of chest diseases, (56.6%) & (38.3%) in polishing & filling workers respectively.

Effect of malonyl malonanilide dimers on the thermal stability of nitrocellulose

Three malonanilide dimers (MA2-MA4) were prepared by the reaction of ethyl malonate with malonanilide derivatives (M2-M4). These dimers were investigated as new stabilizers for nitrocellulose. The evaluation process has been performed through Bergman-Junk (BJ) test, thermal analysis measurements (TGA and DSC) and kinetic parameters calculations (E(a)). The comparative study between mass spectra and thermal analysis of the new dimers helped in resolving the thermal decomposition mechanisms for the new dimers. It was found that the new dimers especially (MA2 and MA4) showed better stabilizing effect for the nitrocellulose than the centralite 1 (C1) which is the common stabilizer.

Synthesis, chemical and enzymatic hydrolysis, and bioavailability evaluation in rabbits of metronidazole amino acid ester prodrugs with enhanced water solubility

A series of amino acid esters (3a-e) have been synthesized and evaluated as potential prodrugs of metronidazole with the aim of improving aqueous solubility and therapeutic efficacy. The aqueous solubility and the lipophilicity (expressed as the log P value) of metronidazole and its esters were investigated. In general the prodrugs revealed enhanced water solubility compared with metronidazole. N,N-diethylglycinate hydrochloride (3a) and 4-ethylpiperazinoacetate (3e) derivatives displayed higher aqueous solubility, which exceeded that of the parent drug by factors of approximately 140 and 100, respectively. All the esters revealed lower log P values than metronidazole except for the 4-phenylpiperazinoacetate derivative (3f), which was 6.5-times more lipophilic than metronidazole. The hydrolysis kinetics of the esters were studied in aqueous phosphate buffer (pH 7.4) and 80% human plasma at 37 degrees C. In all cases the hydrolysis followed pseudo-first-order kinetics and resulted in a quantitative reversion to metronidazole as evidenced by HPLC analysis. The prodrugs exhibited adequate chemical stability (half-life, t1/2, 4-16 h) in aqueous phosphate solution of pH 7.4. In 80% human plasma they were hydrolysed within a few minutesto metronidazole. The esters 3d (methylpiperazinoacetate derivative) and 3f were exempted since their t1/2 values were approximately 2.5 and 8.5 h, respectively. A comparative pH-rate profile study of N,N-diethylglycinate hydrochloride (3a) and 4-ethyl-piperazinoacetate (3e) derivatives in aqueous buffer solution over the pH range 2.2-10 was investigated. The results indicated that 3a showed marked stability at pH 2-6 followed by accelerated hydrolysis at pH 7.4. The basic ester 3e was found to be less stable at lower pH values but exhibited comparative stability at physiological pH. Moreover, in-vivo experiments in rabbits revealed a higher metronidazole plasma level with sustained release characteristics within the prodrug-treated animals (10- and 2.5-fold) as compared with the parent drug-treated group. In conclusion, the designed amino acid esters 3a and 3c-e might be considered as good candidates for water-soluble prodrug forms of metronidazole.

Evaluation of malonanilides as new stabilizers for double-base propellants

Five malonanilide derivatives (M1-M5) were prepared by the reaction of ethyl malonate with aniline derivatives. These compounds were investigated as new stabilizers for double-base propellants (DBPs). The evaluation process has been performed through thermal stability tests, thermal analyses measurements (TGA and DSC) and kinetic parameters calculations (E(a)). The results of the new stabilizers were compared with the results of the classical stabilizer N, N-diethyldiphenyl urea. It has been found that o- and p-dinitromalonanilides, in particular, showed better stability effect for DBPs than the classical one.

Improvement of availability of allopurinol from pharmaceutical dosage forms I - suppositories

Solid dispersion and crystallization of a very slightly water-soluble drug, allopurinol, were prepared using urea, sodium salicylate and beta-cyclodextrin (beta-CD) as carriers. The spectroscopic infra-red (IR), differential scanning calorimetry (DSC) and powder X-ray diffractometry (PXRD) data indicate a role of these carriers in decreasing the crystallinity of allopurinol and complexing abilities. Solid dispersion and crystallization of the drug with these carriers were used in suppository formulations to investigate their role in enhancement of drug release through the membrane barrier. The bases used included Suppocire AM and the mixture of polyethylene glycols (PEGs). The release rates of allopurinol from lipophilic and hydrophilic suppository bases were examined and compared with those obtained for their inclusion compounds incorporated in the same bases. The prepared suppositories were evaluated for in-vitro drug release, when fresh and on storage. The release of pure allopurinol from the lipophilic base was remarkably higher than that from the hydrophilic one. The release of allopurinol from lipophilic as well as hydrophilic bases was significantly enhanced by crystallization of the drug from 5% w/v of sodium salicylate. Allopurinol crystallized from sodium salicylate, showed enhanced release reaching about 100% in 1 h from the Suppocire AM base. The obtained data from these experiments proved the superiority of the PEG formulations containing coevaporates of the drug to sodium salicylate, ratio 1:1, or of the drug to beta-CD, ratio 1:2; T(90%),12 and 36 min, respectively. A significant decrease of uric acid excretion in rabbits was observed after rectal administration of suppositories containing allopurinol crystallized from sodium salicylate.

Production of organic acids from kitchen wastes

This study involves the production of short-chain organic acids from kitchen wastes as intermediates for the production of biodegradable plastics. Flasks, without mixing were used for the anaerobic conversion of the organic fraction of kitchen wastes into short-chain organic acids. The influence of pH, temperature and addition of sludge cake on the rate of organic acids production and yield were evaluated. Fermentations were carried out in an incubator at different temperatures controlled at 30 degrees C. 40 degrees C, 50 degrees C, 60 degrees C and uncontrolled at room temperature. The pH was also varied at pH 5, 6, 7, and uncontrolled pH. 1.0 M phosphate buffer was used for pH control, and 1.0 M HCl and 1.0 M NaOH were added when necessary. Sludge cake addition enhanced the rate of maximum acids production from 4 days to 1 day. The organic acids produced were maximum at pH 7 and 50 degrees C i.e., 39.84 g/l on the fourth day of fermentation with a yield of 0.87 g/g soluble COD consumed, and 0.84 g/g TVS. The main organic acid produced was lactic acid (65-85%), with small amounts of acetic (10-30%), propionic (5-10%), and butyric (5-20%) acids. The results of this study showed that kitchen wastes could be fermented to high concentration of organic acids, which could be used as substrates for the production of biodegradable plastics.

Degumming of crude palm oil by membrane filtration

The application of membrane separation in palm oil refining process has potential for energy and cost savings. The conventional refining of crude palm oil results in loss of oil and a contaminated effluent. Degumming of crude palm oil by membrane technology is conducted in this study. The objective of this research is to study the feasibility of membrane filtration for the removal of phospholipids in the degumming of crude palm oil, including analyses of phosphorus content, carotene content free fatty acids (as palmitic acid), colour and volatile matter. A PCI membrane module was used which was equipped with polyethersulfone membranes having a molecular weight cut off of 9,000 (type ES209). In this study, phosphorus content was the most important parameter monitored. The membrane effectively removed phospholipids resulting in a permeate with a phosphorus content of less than 0.3 ppm The percentage removal of phosphorus was 96.4% and was considered as a good removal. Lovibond colour was reduced from 27R 50Y to 20R 30Y. The percentage removal of carotene was 15.8%. The removal of colour was considered good but the removal of carotene was considered insignificant by the membrane. Free fatty acids and volatile matter were not removed. Typical of membrane operations, the permeate flux decreased with time and must be improved in order to be adopted on an industrial scale. Membrane technology was found to have good potential in crude palm oil degumming. However, an appropriate method has to be developed to clean the membranes for reuse.

Feasibility study on the utilization of rubber latex effluent for producing bacterial biopolymers

Rubber latex effluent is a polluting source that has a high biochemical oxygen demand (BOD). It is estimated that about 100 million liters of effluent are discharged daily from rubber processing factories. Utilization of this effluent such as the use of a coupled system not only can reduce the cost of treatment but also yield a fermentation feedstock for the production of bioplastic. This study initially was carried out to increase the production of organic acids by anaerobic treatment of rubber latex effluent. It was found that through anaerobic treatment the concentration of organic acids did not increase. Consequently, separation of organic acids from rubber latex effluent by anion exchange resin was examined as a preliminary study of recovering acetic and propionic acids. However, the suspended solids (SS) content in the raw effluent was rather high which partially blocked the ion-exchange columns. Lime was used to remove the SS in the rubber latex effluent. After the lime precipitation process, organic acids were found to adsorb strongly onto the anion exchange resin. Less adsorption of organic acids onto the resin was observed before the lime precipitation. This was probably due to more sites being occupied by colloidal particles on the resin thus inhibiting the adsorption of organic acids. The initial concentration of organic acids in the raw effluent was 3.9 g/L. After ion exchange, the concentration of the organic acids increased to 27 g/L, which could be utilized for production of polyhydroxyalkanoates (PHA). For PHA accumulation stage, concentrated rubber latex effluent obtained from ion exchange resins and synthetic acetic acid were used as the carbon source. Quantitative analyses from fed batch culture via HPLC showed that the accumulation of PHA in Alcaligenes eutrophus was maximum with a concentration of 1.182 g/L when cultivated on synthetic acetic acid, corresponding to a yield of 87% based on its cell dry weight. The dry cell weight increased from 0.71 to 1.67 g/L. On the other hand, using concentrated rubber latex effluent containing acetic and propionic acids resulted in reduced PHA content by dry weight (14%) but the dry cell weight increased from 0.49 to 1.30 g/L. The results clearly indicated that the cells grow well in rubber latex effluent but no PHA was accumulated. This could be due to the high concentration of propionic acid in culture broth or other factors such as heavy metals. Thus further work is required before rubber latex effluent can be utilized as a substrate for PHA production industrially.

The performance and kinetic study of membrane anaerobic system in treating POME. Palm oil mill effluent

The application of the three known kinetic models on MAS (membrane anaerobic system) process treating the POME and the overall MAS treatment efficiency were investigated. The MAS consists of a cross-flow ultrafiltration membrane (Model Micro 240) for solid-liquid separation. Six steady states were attained over a range of mixed liquor suspended solids of 12,681 - 30,460 mg/l. The study showed a good fitting of the Monod Model (91.1%), Contois Model (98.5%) and Chen and Hashimoto Model (95%) for the MAS treating raw POME at organic loadings between 1.5 kgCOD/m3/d to 6.5 kgCOD/m3/d. The growth yield coefficient, Y, was found to be 0,604 kg VSS/kgCOD while the specific microorganism decay rate was 0.099 day(-1). The k values were in the range of 0,242 to 0.425 mg COD/mg VSS.d and the microm values were between 0.145 to 0.257 day(-1). Throughout the study, the removal efficiency of COD was 83.2 to 97.97%. The methane production rate was between 0.262 to 0.473 l/g-COD-utilised/d. The MAS treatment efficiency was greatly affected by SRT and OLRs. In the study, membrane fouling and polarization at the membrane surface played a significant role in the formation of the strongly attached cake layer limiting membrane permeability

Respiratory complications after thyroidectomy and the need for tracheostomy in patients with a large goitre

BACKGROUND

Thyroidectomy for a large goitre carries a relatively high risk of postoperative respiratory obstruction which may necessitate tracheostomy.

METHODS

One hundred and three patients with a large goitre who underwent thyroidectomy were studied prospectively. The presence or absence of six preoperative predictive factors for the development of serious postoperative respiratory obstruction was recorded. These factors were: goitre for more than 5 years, preoperative recurrent laryngeal nerve palsy, significant tracheal narrowing and/or deviation, retrosternal extension, difficult endotracheal intubation and thyroid cancer. Tracheostomy was performed on the basis of clinical judgement.

RESULTS

Postoperative respiratory complications occurred in 32 patients (31 per cent), and were obstructive in 24 patients and not obstructive in eight. Tracheostomy was necessary in 13 patients (13 per cent). Tracheomalacia was the most common indication (n = 5). There were no deaths. At least four of the six risk factors were present in nine of the 13 patients who underwent tracheostomy compared with two of the 90 patients who did not.

CONCLUSION

Multiple preoperative risk factors in a patient with a large goitre may be useful in predicting the need for planned tracheostomy following thyroidectomy.

Synthesis of 2,5-disubstituted-1,4-benzoquinone derivatives as potential antimicrobial and cytotoxic agents

A number of 2,5-disubstituted-1,4-benzoquinone derivatives were prepared and characterized by elemental analysis, infrared (IR), nuclear magnetic resonance (1H-NMR), and mass spectra (MS). These compounds and their synthetic precursors were evaluated for their in vitro antimicrobial and cytotoxic activity. The most potent antimicrobial compound was the thiadiazolyl derivative 4b, which was 2- to 4 times more active than the antimicrobial drug sulfathiazole. All the tested compounds were active in the Brine Shrimp Lethality (BS) Test. Compound 4e which was the most active in the BS test was also found to possess a significant cytotoxicity against two tumor cell lines. Some of the compounds were found to be mutagenic at relatively high concentration.

Kojic acid production by Aspergillus flavus using gelatinized and hydrolyzed sago starch as carbon sources

Direct conversion of gelatinized sago starch into kojic acid by Aspergillus flavus strain having amylolytic enzymes was carried out at two different scales of submerged batch fermentation in a 250-mL shake flask and in a 50-L stirred-tank fermentor. For comparison, fermentations were also carried out using glucose and glucose hydrolyzate from enzymic hydrolysis of sago starch as carbon sources. During kojic acid fermentation of starch, starch was first hydrolyzed to glucose by the action of alpha-amylase and glucoamylase during active growth phase. The glucose remaining during the production phase (non-growing phase) was then converted to kojic acid. Kojic acid production (23.5 g/L) using 100 g/L sago starch in a shake flask was comparable to fermentation of glucose (31.5 g/L) and glucose hydrolyzate (27.9 g/L) but in the 50-L fermentor was greatly reduced due to non-optimal aeration conditions. Kojic acid production using glucose was higher in the 50-L fermentor than in the shake flask.

Synthesis of 2-[4-(4-iodophenyl)-1-piperazinylmethyl]-1,3,4-oxadiazole and its potential application in the indirect iodination of carbonyl compounds

The synthesis of 2-[4-(4-iodophenyl)-1-piperazinylmethyl]- 1,3,4-oxadiazole is discussed. Hydrolysis of the oxadiazole followed by condensation with 3 beta-hydroxy-5-androsten-17-one gave the hydrazone. This synthetic sequence could be applied for the indirect iodination/radioiodination of ketosteroids.